I. 'IHIlllir df o^.cf "mi, m ^ THE RAY SOCIETY. INSTITUTED MDCCCXLIV. This volume is issued to the Subscribers to the Ray Society for the Year 1882. LONDON MDfiCCLXXXIII. MONOGRAPH OF THE BEITISH APHIDES VOL. IV. GEORGE BOWDLER BUCKTON, FELLOW OF THE ROYAL, LINNEAN, AND CHEMICAL SOCIETIES OF LONDON ; CORRESPONDING MEMBER OF THE ACADEMY OF NATURAL SCIENCES, PHILADELPHIA. ~ifvK\ai ixev /xixpal p.dKa juvpiai, avrap eKao-njv S&KVei \fiv\\iSCuiv ixiKftOTtpoiv aye'Aij' >pv\\iS(iov yei'edi' eVep' av woKv /xeiova Sanvei ^uAAi'St"' oil Aijyei trpayp.' e's aneipov iov. — MeAeaypov, wj Sd rives, 2Tp«i/uo6ou' LONDON: PRINTED FOR THE RAY SOCIETY. MDCCCLXXXIII. m war with falsehood to the knife, And not to lose the good of life. * # * * As far as might be to carve out Free space for every human doubt, That the whole mind might orb about. To search thro' all I felt or saw, The springs of Life, the depths of awe, And reach the law within the law. Tennyson— The Two Voices. PRINTFD BY J. E. ADLARD, BARTHOLOMEW CLOSE. 7U62UG9901 PEEFACE. On introducing this concluding volume to the reader, I tender my sincere thanks to the Members of the Council of the Ray Society for undertaking the publication of my Monograph, and for the courtesy which they have shown me in fulfilling my wishes as to the form it should assume. Prof. Helmholtz well remarks that " The materials of a monograph must be united by a logical process ; and the first step is to connect like with like, and to elaborate a general conception embracing them all." Again, elsewhere, "A digest or catalogue may be likened to a good lexicon ; with which almost a tyro of the present day can achieve results in the interpretation of the classics, which an Erasmus, with the erudition of a lifetime, could hardly attain." Some may perchance think that this Monograph has attained proportions unnecessarily large. The general reader, on the one hand, may take exception to its detail. The competent biologist, with more truth perhaps, may complain of omissions as well as com- missions. The first may call to remembrance and apply the causticity of Montaigne when he says, " The trade of the rhetorician is to make things appear and VI PKEFACE. seem great, just as a shoemaker can make great shoes for little feet." An attempt has been made so to blend the life-history of Aphides with their morphology, as to render the subject not wholly uninteresting to the general reader, and yet to furnish details necessary for the systematist : but the latter may reasonably ask that the facts shall not be put before him in a form unnecessarily dry. The depths of Biology are as unfathomable as those of any other science. The long list of authors I furnish at the end of this volume, though far from exhaustive, will show how much attention has been already paid to this group of insects ; and yet I am sensible of many omissions, and that much has yet to be discovered with reference to my subject. It would almost seem that more may be written on this one single insect family than on the life-history of a family of the carnivorous Vertebrata ; — we may instance the Felida3. Indeed, several years' study is required to pro- duce a complete life-history of some insects, and they may require special treatises to exhaust the subject. Through the kindness of M. J. Lichtenstein, I am enabled to give a short but compendious history of the grape-vine pest, Phylloxera vastatrix. His researches and familiarity with the whole tribe will make his observations acceptable to all. Although not strictly within the province of a treatise on British Aphides, a chapter has been devoted to the question of the general existence of Aphides in early geological times. The author has freely consulted several important memoirs of Prof. Oswald Heer, and also his valuable treatise on the ' Primeval World of Switzerland.' .Much help lias likewise been obtained PREFACE. Vll from Mr. Samuel Scudder's numerous published papers on Fossil Insects; particularly from those sections bearing on the fossil Aphides found in the beds of the Florissant basin of Colorado. This gentleman has most liberally allowed me to draw from some of his plates which have not yet been published. Although these forms are American, they have characters almost identical with our recent European genera. To these sections I have also added a short account of some of the Aphides which have been included in masses of amber. The author trusts that the preliminary remarks of this and the preceding volumes will be a sufficient acknowledgment of the sources from which much of his information has been drawn. Towards the close of this volume I have thrown together some of the principal known facts relating to the reproduction and embryology of Aphis ; and by way of introducing this subject, I have attempted a sketch bearing on the general growth of the ovum of insects. I wish here to acknowledge my indebtedness to the works of Dr. Allen Thomson, Professors Huxley, Forster, and Balfour, Ray Lankester, Ernst Haeckel, Dr. A. Brandt, E. Balbiani, and others. The late Prof. Balfour's recent treatise on ' Comparative Embryology ' is a mine of wealth to all biologists. In my former volumes I expressed, as strongly as I was able, my obligations to many friends ; and I will not here repeat my thanks. One gratification in the study and illustration of natural phenomena is a con- tinual growth of genial correspondence with those of kindred thoughts and tastes. I must here, specially offer my thanks to Prof. Vlll PREFACE. Huxley, who kindly made some valuable criticisms on reading my proofs on the ' Morphology and Reproduction of Aphis ; ' and also to Prof. Thomas Wiltshire and Prof. Rupert Jones, both of whom have suggestively helped me to get all my four volumes through the press. The subscripture to the Greek verse on my title page is very obscure : and it will invite and test the ingenuity of many, as to whether the author be ancient or modern. Recently I have received from an anonymous writer, who shrouds himself in euphonious but somewhat " stiff " Greek, a witty suggestion as to the vexed derivation of Linneus' word Aphis. It may be fairly inferred that both these effusions are the product of the same, or of kindred spirits. 'O boKifiuiraros rfjs (3av €k \pvXXi8iu)v re (ftVTevojp fivpia fivpiaKis tiktw, tu 8e r€Kv' eiririKTei [XvptaKis TroXXanXaaiov yevos, ibvirep eKncrrov dptTTTpa TOKevai iXois Xa/uvpovs eviTt-qtfiv oburras v\piyoi'oy Trpoybtoiai, ra fieiora 8' 07rAdrep' aXlcijv fieiloai wpeo-fivrepois t\ov b* w/i0j3i'|0ov Kai 7rafi7/i' aXiaorov oi^vpoiai f5poTO~i(riv. The identity and unity of phenomena connecting the higher with the lower forms of living animals, is now too well acknowledged to want urging ; yet the words of Leon Dufour may be quoted in conclusion as apposite. " Ce n'est pas seulement a rechercher et a con- naitre les productions naturelles qui par leur grandeur sont a la portee facile de ces sens, que l'homme avide d'instruction doit consacrer ses soins et ses loisirs ; il trouvera des sujets tout aussi dignes de son culte, dans les etres qui par leur petitesse occupent les derniers degres de Fechelle organique et semblent d^fier son attention L'elephant massif, l'orgueilleux Vir sapiens, n'ont pas plus couter au Createur, que l'impalpable byssus .... et la punaise." Weycombe, Haslemere ; March 7th, 1883. VOL. IV. BRITISH APHIDES. YOL. IV. GENERAL SYNOPSIS. Vol. I. T Aphidin^;. . Upper wing with p^q a twice-forked M J cubitus ; under wing with two oblique veins. Antennse with 7 _ joints. a l-M j GENERA. PAGE^ ,Absinthii Alliarige . 151 . 123 Artemisiae . 155 Avellanae 149 Carnosa . 144 Chelidonii . 121 * Cichorii . 163 Oircumflexa . 130 Convolvuli . 148 Cyparissiaa . 113 Dirhoda . 132 Fragariae . 125 Granai'ia . 114 Hieracii . 126 Jaceaa . . 153 Lactucse . 139 Longipennia . 146 Latea . . 119 Menthae . 120 Millefolii . 127 I. Muralis . 157 HONOPHOBA. U Olivata . . 164 Pelargonii . . 136 Pisi . 134 Polygoni . 123 R0S33 . 103 „ var. gl mca. 109 Rosarum . 150 Rubi . . 140 „ var rufa j, vol. iv, p. 105 , Scabiosae . 112 Scrophulariae . 137 Sisymbrii . 160 Solidaginis . . 156 Sonchi . . 161 Tanaceti . 151 Tanaceticola . 159 Tussilaginis . 159 ,Ulmaria3 Urticaa . . 134 . 143; VOL. IV. BRITISH APHIDES. Aphidin^e (continued). GENERA. PAGE, f Galeopsidis . . 171] Humuli . Ififi Phorodon. l j „ var. Malabeb 168 c Cerasi . . 174 in. \ Gracilis . 176 Myzus. « 1 Persicae . 178 ( Ribis . . 180 IV. f Drepanosiphum.- (. Acerina . 185 Platanoides . . 183 Amphorophora. (. Ampullata . . 187 YI. C Megoura. i (. Vicise . . 188 Vol. II. "Berberidis . . 14 Diantbi . 15 YII. Lactucae . 10 Rhopalosiphum. A Ligustri . 13 Nympbaese . . 12 I Ribis . . 9 OQ VIII. j Melanoxanthtjs. u { Salicis . . 21 o ( ' Caprese . 27 IX. \ Foeniculi . 26 SlPHOCORYNE. o . Pastinaceae . 24 ( ^Xylostei . 25 r Abietina . 43 Acetosa3 . 80 Amygdali . 104 Atriplicis . 87 Aucuparisa . 76 Bellis . . 98 Brassicao . 33 Cavdui . . 92 Crata)garia . 37 X. Aphis. > Cratasgi . 35 Cucurbiti Edentula . 56 . 39 V Epilobii . 71 Euonymi . 72 Farfarea . 68 Hederse . 75 Hieracii . 67 Iustabilis . 94 Jacobffia) . 79 Labnrni . 86 ^Lentiginis . 59 ) GENERAL SYNOPSIS. GENERA. X. Aphis (continued). Aphidin^; (continued). XL Hyalopterus. XII. Chaitophorus. XIII. Pterocomma. XIV. Cryptosiphum. XY. Brachycoltts. "Lychnidis Mali . MalvsB . Myosotidis Opima . Padi . Papaveris Pedicularis Penicillata Petasitidis Pruni . Pyraria Pyri . Rumicis Saliceti Sanibucaria Sambuci Scabiosse Sedi Sorbi Subterranea Tanacetina Urticaria ^Viburni f Aruudinis J Dilineatus J Eriophori | Melanocephalus Pruni . LTrirhoda C Aceris . Betulse . Capreaa •{ Leucomelas I Populeus | Populi . |J3alicivorus < Pilosa . j Artemisia 5 Stellaria? Vol. III. PAGE, . 73 . 44 . 42 . 102 . 101 . 61 . 91 . 41 . 51 . 69 . 64 . 53 . 97 . 81 . 52 . 95 . 99 . 55 . 90 . 58 . 38 . 63 . 50 . 77 . Ill . 113 . 117 . 116 . 110 . 114 . 121 . 139 . 136 . 135 . 137 . 140 . 134 . 143 . 145 . 147 XYI. Calliptertjs. Betularius Betulicola Cai'pini Castanet j Ooryli . I Querceua l^Quercus 14 15 19 26 17 24 21' BRITISH APHIDES. V 9 a LACHNINiE. Upper wing with twice-forked cu- bitus ; under wing with two oblique veins. Antennae with 6 joints. SCHIZONEUEIN^. [ Cubitus once | forked. Lower •{ wings with two I oblique veins. r PeMPHIGINjE. Cubitus not forked ; lower wings with one | or two oblique | veins. -\ Cubitus once forked ; lower wine: with one oblique vein. GENERA. XVII. Ptekocallis. fAlni . < Juglandicola (.Tilise . Fagi XVIII. Phtllaphis. XIX. C j ugland i s Pttchodes. (. & XX. Lachntjs. XXI. Stomaphis. XXII. Paracletus. XXIII. Trama. XXIV. Dryobius. XXV. SCHIZONETJRA. XXV bis. Cerataphis. XXVI. Pemphigus. XXVII. Tetraneura. (Aploneura.)* (Toxoptera.) XXVIII. TlIELAXES. XXIX. Glyphina. f Agilis . Cupressi Juniperi Longipes -{ Macrocephalus Picege . Pini . Pinicolus ^Viminalis < Quercus < Cimiciformis \ Troglodytes . f Croaticus (_ Roboris fCorni . j Fodiens J Fuliginosa "j Lanigera j Lanuginosa ^Ulini . < Latania3 fBursarius Filaginis J Fuscifrons j Lactucarius Pallidus l^Spirothecae [ Ulmi . Vol. IV. Dryophila f Betulaa . \ Pilosa . PAGE^ . 31 . 32 . 34 . 37 . 40 . 47 . 46 . 44 . 59 . 48 . 58 . 50 . 52 . 53 . 62 . 67 . 68 74 m 71 l! 107 94 96 89 104 97 197 117 128 113 124 127 122 131 * Vide vol. iii, pp. 135, 136. GENERAL SYNOPSIS. r CHERMESINiE. Upper wing with j only three veins ; j lower wing with | one oblique vein. I Rhizobiin^. Winged forms un- \ known. GENERA. XXX. Chermes. f Abietis Atratus «j Corticalis j Laricis . l^Pini . C Punctata < Quercus Phylloxera. , |^ astatrix XXXI. XXXII. Forda. XXXIII. Tychea. XXXIV. Endies. XXXV. Rhizobius. PAGE . 24 . 39 . 23 . 33 . 40 . 45 . 49 52,57 ( Forinicaria . . 83 (_Viridana . . 85 fEragrostidis . 89 | Phaseoli . . 90 •{ Setaria3 . . 88 | Setulosa . . 87 [_Trivialis . . 86 C Carnosa . . 92 < Formicina . .91 CPellucida . . 91 \ Graminis (Poee) . 93 Genus XXVIII.— THEL AXES, Westwood* Plattlaus. Rostrum long, reaching to the third coxse. Second joint very long and thin, third joint thickened, the last pointed. > Antennae rather short, five-articulate, if the nail-like terminal process be not counted. The third joint equal to the two following, taken together. Cornicles wart-like and very short. Wings carried horizontally, and folded one over the other when at rest. Upper wing with a single furcated cubital vein, the other veins as in Pemphigus. Lower wing has only one single oblique vein, springing from the cubitus. The eyes in the apterous forms are rudimentary. Kaltenbach points out that they are very small, and that they want the tubercle. Von Heyden's genus Vacuna has been so generally received by Continental authors that some may feel regret that any change should be made in the name. However, it now seems granted, as a general rule, and in fairness, that priority in descriptions of genera shall decide between rival names. Prof. Westwood by some years has precedence over Von Heyden, and therefore I adopt his nomenclature as above. * From 3>jXa£uv, to bear mammae, alluding to the papilliform nec- taries. O BRITISH APHIDES. Thelaxes dryophila, West. Plate CXV, figs. 1 — 7. Vacuna dryophila, Heyd., Kalt., Koch, Pass., Licht. Aphis dryophila, Ratz., Schr. Vacuda, Amyot. Cinara quercus, Sir 0. Moseley. Apterous viviparous female. Queen Aphis. Inch. Millimetres. Size of body O'OOO X 0'055 2-28 X 1*39 Length of antennae 0*035 0*88 Cornicles 0*005 0*12 Oval, flat ; olive-brown, greenish, or chestnut-brown. Rings of the body well marked ; a pale yellowish streak, commencing at the head with diminishing distinctness, passes down the dorsum to the apex ; five dark pore- marks, each surrounded by a pale ring, occur on both sides. Nectaries wart-like, pale, and inconspicuous. Legs and antennaB brown. Eyes very small, and divested of the usual tubercle ; the optical facets, which number only five or six, are set far back on the head. AntennaB about one- third the length of the body ; five-jointed, the third joint much the largest. Body slightly pilose. Rostrum rather short, but this organ is longer in the }^ounger forms. The queen Aphis or fundatrix is, as usual, much larger than her offspring. I'h pa. Inch. Millimetre. Size 0-060x0-030 1-52x0-76 Small, green or yellowish, with a pinkish hue to- wards the head ; slightly mealy, with two pale streaks THELAXES DRY0FH1LA. 9 down the sides; sometimes these streaks are broad and dark. Wing-cases, antennae, and legs pale. Eyes distinct. Winged viviparous female. Inch. Millimetres. Expanse of wings 0*150 3'80 Size of body 0*055 X 0*020 1*39 X 0*50 Antennas 0*025 0*63 Nectaries 0*005 0-12 Head and thorax pitchy brown or shining black. Prothorax paler. Abdomen oval, shining green, more or less mottled. Cornicles brown and very small. Legs green, and of moderate length. "Wings moderate, and folded horizontally ; bronzed and highly iridescent. Their apices rounded. Eyes and ocelli reddish and fully developed. The colours of this insect are very inconstant. Koch describes and figures two marked varieties, one brown, with yellowish legs, the other with a vermilion- red prothorax and abdomen. The rostrum is long and reaches beyond the first body-ring. The sexes of this species are minute. They occur late in the year, and are most plentiful during Novem- ber and December. The male is apterous, and about two-thirds the size of the female. Doubtless from its smallness it was long overlooked or disregarded. Both sexes are distinctly rostrated at their early stages, but possibly they lose these organs at a subse- quent moult, since the Continental specimens are described as mouthless. All the males under my observation have been apterous, like the oviparous females. Male. Inch. Millimetre. Size of body 0-020 X 0*010 0*50 X 0*25 Antennas 0*015 0*38 Oval. Colour lemon-yellow. Antennas sooty grey. 10 BRITISH APHIDES. Abdomen greenish, with a double row of dorsal spots. Antennae and legs rather long. Taken in copula with the following. Ociparous female. Oval, wholly dingy green, with brownish stains and streaks passing behind the eyes and over the thorax. Abdomen with four rows of brown spots, and seven smaller dots on each side, marking the sites of certain pores other than the stomata, which last are placed on the inferior surface of the body. Legs and antenna short. The abdominal cavity of the specimen described was almost entirely occupied by two large yellow eggs, the safe delivery of which is a mechanical marvel. Inch. Millimetre. Length of body O035 X 0'020 0-88x0-50. Antennas 0-020 0-50 Cornicles None. The prevalence of Thelaxes in England is variable both as to quantity and locality. Some years it is very abundant, whilst in other years it is difficult to find. In the late spring of 1871 many twigs and young shoots of Qucrcus sessilij!<>rn'i< which will remain throughout the winter. Thus these progenitors shelter their eggs even more securely than the progeni- tors of those which oviposit on plants. M. Balbiani further tells me that he has also made observations on phylloxeridj:. 75 Siphonophora solidaginis, but the results are less com- plete than those of 8. mittefolii. In September the males and females were often seen coupled together under the flower heads of Solidago, but singularly, as in the other mentioned case, the egg was never detected on the food-plant. The gravid females descended the stalks, and might be found at all heights, more than two or three inches from the ground. M. Balbiani thinks that these Aphides abandon the plants of Solidago vergaurice, which, in summer, harbour the viviparous broods, in order to lay their eggs on some of the low plants in the immediate neighbourhood; exactly as has been seen to be the habit of Siphonophora millefolii. V. BHIZOBIINuE, PASS: WINGED FORMS UNKNOWN. KHIZOBIIN^]. 79 INTRODUCTION. Classification is based on certain observed affinities and agreements with types, or divergencies therefrom. In proportion as a grouping of animals accords with their biology, morphology, and the like, will any given arrangement assume a scientific value. It is, however, obvious that all classifiers do not attach equal value to the same characters. A consensus of opinion, however, will render any schemes they may raise more likely to be in accordance with natural laws. Genera, however, may be temporally adopted for mere convenience and a means of study, until such time as a better acquaintance with embryology and a true phyllogeny will permit a more perfect grouping. These remarks will more particularly apply to the tribe immediately following. Perhaps of all divisions of the family Aphidiuse no group presents so great difficulties in classifi- cation as that which Passerini has marked under the sectional name of RhizobiinEe. The fossorial habit shown by all the known species, and their attachment to the young roots of various plants, is by no means confined to Aphides of this tribe. We have noted subterranean habits in Sipho- nophera, Aphis, Pemphigus, Schizoneura, Paracletus, and Trama, therefore the meaniug of the term is not exclusive, as a generic term should be. Linnseus's well-known words, " Nomina si nescis, perit et cognitio rerum," may go too far; but a name is a first step towards an exact knowledge of a thing. It may be a question whether the names of genera should ever express or involve an hypothesis. Burmeister described a species which burrowed at 80 BRITISH APHIDES. the roots of Hioracium, to which he gave the name Bhizobiu8 subterraneus. Signor Passerini, for conve- nience, has adapted its characters for a sectional group, and I here follow the lead of so good a naturalist. No winged forms have yet been discovered in this group. Thus we lose the valuable help which would have been afforded by a study of the wing-veining and other characters attending a metamorphosis into the imago. Again, the simplicity of the tarsal joints, and the little light thrown on the matter by any reliable variation in the mouth parts, and the want of all fixed banding of pigment or colour on the bodies, render it very difficult authoritatively to decide what should be the points of a diagnosis. As an illustration of the variability of a genus I cannot do better than quote Passerini's words, which, though they apply particularly to the description of a single insect, Bhizobius menthce, yet equally well suit all the English species of this tribe. With reference to the antennal joints, he says, 11 Secundum astatem antennarum articuli numero vari- ant. In junioribus articuli tres tantum extant, quorum extremus caateris valde longior. Orescente state hie apico dividitur, unde antennas quadri-articulatae fiunt; et deinde articulus tertius, omnium sua vice longior, apicem versus bis dividitur donee antennae sexarti- culataa evadunt, articulis subaequalibus." Notwithstanding these undefined characters, consi- derable interest attaches to the group on account of the peculiar economy shown by its members. When the insects are regarded as a whole, they certainly show to the eye a peculiar aspect, which separates them from all the genera previously described. One of the notable life-peculiarities concerns their relations to ants. With few exceptions, all the species are denizens of ant-hills ; and it is singular how insects of such diverse habits and conformation can live and thrive together. Many isolated observations have been made with RHIZOBIIN^]. 81 reference to this very curious subject of what may be called Paracletism. More correctly, perhaps, its dis- cussion belongs to the historian of Formica than to that of Aphis, since the Ant, with its superior intelli- gence (?), chooses the company of Aphis, and makes it more or less to conform to its own economy. But the question arises, and has not been yet satis- factorily answered, what part in the economy of Formica, &c, does Aphis really take ? From the days of Huber the older, and the younger, we have been aware that Ants draw occasional food from these creatures, and this Monograph has already noted that many species of Aphis voluntarily yield honey-dew from their nectaries at the call of the Ants ; but what is to be said of those insects which possess no nectaries, as is the case with the Bhizobiina3 ? True, they have certain dorsal pores apart from the stomata ; and in some cases the aerial drops of liquid may be seen to exude from such orifices. In these root-feeding Aphides, however, the func- tion of the pores is to exude waxy or silk-like fila- ments, which are employed to cover and protect the insect from the water of the soil and to make a nidus for its eggs. I am far from denying that these pores are capable of giving food to the Ants, but clear obser- vation to substantiate the fact is yet desirable.* Perhaps this question may be relevant to the matter : What is the significance of the presence of the blind Claviger, of Julus,of Oniscus, and Scolopendrum, which equally share the shelter of the Ants' nest ? It cannot here be argued that they are kept by the Ants for food. The whole question is an interesting one, and is sufficiently puzzling ; for these curious fostering habits obtain also in other Hymenoptera. Thus, the handsome Apathus barbatellus is the petted, * Kaltenbach is distinctly of this opinion. He says of Forda, " Dieses Thierchen gibt durch die Afterwarze zuweilen an Tropfchen Fliissigkeit von sich, welche von den Ameisen begierig aufgeleckt wird."— Kalt., « Mon. der Pilau.,' p. 210. VOL. IV. 6 82 BRITISH APHIDES. but apparently idle, tenant of the nest of the common humble-bee, Bombus terrestris, and numerous similar examples may be cited. As regards the association of ants and Aphides it may be remarked that the light, sandy, and warm locality chosen by Ants for their nests arc just those which the subterranean Aphides would choose. Mr. James Hardy, the active naturalist, of Cockburns-path, Northumberland, who has paid attention to the root Aphides not uncommonly found on the moors around writes to me, " "When Fordaformicaria prevailed in the nests of Formica fuliginosa I noticed that the ants paid no attention to them when the hillocks were disturbed. The Aphides slowly re-covered themselves with earth, and those which failed to do so were left quite unnoticed by the numerous ants running about them." In other cases, and notably in that of Formica umbrata, shortly after a similar disturbance, the Aphides were carried off by the Ants, " and they and I had a contest about a particular example." The Ants are in the habit of keeping open runs to carry their offspring nearer to the light and heat, and these runs afford convenient and free spaces also for entrance of the Aphides.* In many cases the Ants doubtless choose for their nest such tufts of grass on a dry hillock as are already infested by Aphides. This is a more simple operation than a marauding expedition, attended by a forcible transplantation of Aphides from the leaves of plants to subterranean cavities, as noted by Huber. Such a change of life seems to be very improbable, and involves so many difficulties which it would be well to have removed. Goedartf was I think the first to observe the friendly relations between Ants and Aphides. He went so far as to imagine conversations between the two insects relating to the attacks of their enemies and the like. * Kale. • Hon.,' p. 210, " Veini Zutritt dcr kiihlern Luft von den meiscn in eleven Gauge gesohleppt." •f- Goedart, ' Do Inscrtiw.' London, los.y FORDA FORMIOARIA. 83 Genus XXXII.— FORDA,* Heyden. Ant-Aphis. Ameisenlaus. Antennas 5 -jointed, the last articulation furnished with a small tubercle or nail. The third joint much the longest. Eyes very small. Abdomen convex. Cornicles none. Tarsus provided with two claws. Winged forms unknown. The species of this genus occurs in small scattered companies. They feed on the fine fibres of the roots of various grasses. They very commonly affect the nests of Formica flava. Both Kaltenbach and Passerini consider the above- noted tubercle to be a true antennal joint. As it is very small, and is not articulated to the fifth joint, I do not count it such. Koch remarks that the young have much resem- blance to Trama. They, however, may be distinguished from such by their more simple antennas and minute eyes. The eyes of Trama are rather large than otherwise. Forda formioaria, Heyd. Plate CXXVI. Bhkoterus vacca, Hartig. Forda formicaria, Heyd., Kalt., Koch, Pass. Viviparous female* Very variable as to size and colour. Large specimens measure — Inch. Millimetres. Length of body O'lOOxO'060 2-53 X 1*52. Antennse 0-040 1*01. * Probably from/ero, which ordinarily makes latus, but irrregularly fordus, pregnant, or prolific ; thus forda vacca, &c. However, this genus is far less productive than most other kinds of Aphides 84 BRITISH APHIDES. White, greenish, dull yellow, or dark green. Rather glossy. Long oval. Head blunt, smooth. Eyes black, prominent, but very small. Body ringed. Adult specimens often have a dark green stripe half way down the dorsum. Legs moderately long, pale brown. Antenna3 5-jointed, the last of which has a nail, which Kaltenbach counts as a joint. Rostrum stout, and reaches beyond the mid-body. Cornicles none. Young examples are slimmer, and have longer antennse. Their rostra project beyond their tails. Found in light sandy soils, and usually in ants' nests under the root-stocks of various grasses. The speci- mens figured were nesting in close proximity to a colony of Formica flava. In this instance I could trace no connection between the two nests, but there is abundant proof that Forda is a common companion of Ants. One difficulty of separating a particular species from another in such structures consists in the very mixed company that forms these assemblies. Thus in the same nest may be taken individuals belong- ing to the Aphis genera, Paracletus, Trama, Forda, and Endeis, and these insects are sometimes supplemented by representatives of Julus, Millepes, Oniscus, and a number of blind beetles. When the full-fed individuals of Forda are gently pressed drops of a clear liquid exude from the dorsal pores, and this liquid probably is acceptable to these ants. This action, under the imaginative fancy of Hartig and of Kirby and Spence, is expanded into the likeness of milch kine, stabled underground for the winter use of the Ants. Mr. J. Hardy kindly sent to me specimens of this insect from Berwickshire. They were smaller than the Haslemere specimens described above. They were found during the summer inhabiting the nests of Myrmica at the roots of JIolcus mollis. Sir John Lubbock also forwarded to me specimens taken in February from similar situations at Becken- ham. FORDA VIRIDANA. 85 Mr. "Walker obtained Forda from the roots of the sow-thistle, Sonchus oleraceus. The habits of Forda formicaria are not apparently in all cases subterranean. I have taken them in April at Haslemere on the green leaves of Triticum repens just above the surface of the ground. I have represented such a modified habit in the plate above alluded to. Koch figures and describes another species of this genus under the name Forda marginata. It is yellowish-white, and possibly may be the same insect as I figure, but the diagnosis agrees only in part. Forda viridana, Bucldon. Plate CXXVII, figs. 1, 2. Viviparous female. Inch. Millimetres. Size of the body 0*080 X 0*050 2*03x1*26. Length of the antennas 0*035 0'88. Oval, dull, pilose, and velvety. Colours variable, from rich chocolate-brown and mouse-brown to an emerald-green ; legs and antennae ginger-brown. Vertex setose. Eyes very small and inconspicuous. Thorax and abdomen much corrugated and domed ; nectaries none. Rostrum long, about three-fourths the length of the body. Tail blunt and carried slightly erect. Claws double, but often seen folded as if they were single. Taken in small companies in Ants' nests covered by tufts of various grasses. It differs from the preceding species in several particulars, and chiefly in beiug smaller, more pilose, and deficient in the green dorsal stripe. It occurs throughout May and June in the dry moors, near Wooler, in Northumberland. Mr. James Hardy informs me the " malachite-green variety " may often be taken in quantity, nesting with Formica fidiginosa. This Aphis is particularly plentiful 86 BRITISH APHIDES. under Aim flexuosa, at the end of May, in the above locality. The brown insect is so commonly mixed with the green, and it agrees so well with it, except in colour, that I assume that the insects are identical. It is not uncommon under the tufts of Carex, on the moors round Alnwick, in Northumberland. I have not met with it under the sand heaps in Surrey. ' Genus XXXIII.— TYCHEA,* Passerlni, Antennas composed of five almost equal joints. Abdomen marginate. Eyes none. Legs short, with two small claws. Cornicles and tail none. Rostrum variable in length according to age. Winged forms unknown. Habitat very similar to the preceding species ; mostly being found at grass roots. Several species also are denizens of Ants' nests. Passerini describes five species as inhabiting Italy, all of which, I believe, are inhabitants of Great Britain. Tychea teivialis, Pass. Plate CXXYII, figs. 3, 4. Viviparous female. Inch. Millimetres. Size of body 0-050 X O040 1-27X1-01. Length of antenna} 0-015 0-38. Globose or ovate, rather flat, yellow or ochreous, smooth. Eyes none. Antenna) very short. The joints vary much in the different moults. In the full- grown insects the third joint is much the largest. In the fundatrix the antennas and rostrum are both * If from Ivxiw, nanciscor, or asscquor, the allusion is not obvious. TYCHEA SETUL0SA. 87 very sliort, the joints being much more equal in length. Taken in Ants' nests, at Beckenham, under tufts of Poa, in November. Passerini gives for food the roots of Triticum vidgare, Cynodon dactylon, Poa trivialis, Festuca duriuscula, fyc. He thinks that possibly Coccus Zece-maidis, of Leon Dufour, may be referred to this species ; and notes that the presumed single claw may probably be due to a mistaken diagnosis.* Tychea setulosa, Pass. Plate CXXVII, figs. 5 — 8. Viviparous female. Inch. Millimetres. Size of body 0'075x 0-060 l-89xl'52. Length of antennas 0'020 0*50. Large, pearly white. Some are circular and domed. Vertex flat, head broad. Antennae 5- jointed, with a rounded button or nail. Third joint much the longest, but there is a tendency to a constriction, which might suggest an additional joint, and make Passerini' s phrase " articulis subasquilongis " more apposite. The whole insect is hirsute and tufted with setas, particu- larly as to the head and antennas. Eyes are merely red specks, and very minute. Legs short, the hinder pairs hardly protrude beyond the body. Tarsi with two claws which fold together so as often to appear but siugle. Rostrum very variable in length. The tip blackish. Cauda rounded. The younger or less developed forms greatly differ in proportion, and show only four antennal joints, with largely extended rostra. Some specimens are fuscous on the head and tail, and all are rather "mealy." The larger insects contained from five to seven embryos. It is remarkable that the eyes and antennas * Vide ' Aphididce Italics,' p. 82. 88 BRITISH APHIDES. of these yet unborn insects are quite as much developed as those of their mothers. It is to be noted also that in these insects the antenna? are disengaged or freed from the body before the other limbs (fig. 8). Taken by Sir John Lubbock in ant-hills near Beck- enham, in April. I kept several individuals alive in moist earth, together with three or four specimens of Formica fla va t for six weeks, without noticing any tendency to become pupae or to greatly vary in their general appearance. These insects partially change their colour and become darker by exposure to light. In Italy the insects nestle at the roots of Oryza mon- tana. Tychea setari^;, Pass. Plate CXXVIII, figs. 1 — 4. Viviparous female. Inch. Millimetres. Size of body 0-060x0-045 1-52x1*18 Length of antennas 0*030 076 Fundatrix short, oval, flat. Colour and texture like white kid leather, some with a faint tinge of green. Antennae very short, about one fourth the length of the body, 4-jointed, with a rounded wart. The third joint much the longest, and often showing a tendency to a constriction in the middle. Eyes very minute. Dorsum has ten or more dusky transverse bands, each terminating with a pore. Antennae, legs, and tail dusky brown. Rostrum short, reaching to the third coxae. Legs hardly project beyond the disc of the body. Cauda conical, sometimes with two or more crescentic marks above it. After several moults the legs and antennae become much longer, the insect becomes rounder, and at the last moult an additional joint may be counted to the antennae. In all stages the body is finely pilose. TYOHEA ERAGROSTIDIS. 89 The tarsi have two claws, but very commonly they are, like the preceding, so folded as to appear but one. Taken in ant-hills at Beckenham. The plate shows an insect just before moulting, when the old skin has separated from the new, yet it still envelops the insect itself. The fundatrix attended by a few young may be taken as early as February. Tychea erageostidis. Plate CXXYIII, figs. 5, 6. Viviparous female. Inch. Millimetres. Size of body 0*050 X 0*040 1*26 X 1*01 Length of antennse 0*040 1*01 Ovoid or nearly circular, glabrous, whitish. Head broad, vertex flat and smooth. Antennal joints five, and almost equal. The fourth as small as the first, the fifth the longest, and furnished with a nail. Eyes and nectaries none. Abdomen domed and ringed. Legs stout and moderately long, claws double, but often folded together. Cauda obtuse. Rostrum about two -thirds the length of the body, but in the young it projects beyond the tail. The queen Aphis or fundatrix is quite different in form, being shuttle-shaped. The antennas, rostrum, and legs are much less developed. Isolated points of red pigment mark the seat of the foetal eyes, which are only partially developed. Taken in ant-hills at Beckenham, and also at the Cheviot, on the roots of Poa annua. This insect feeds also on Panicum glaucum ; and apparently also is viviparous, on the lower exposed leaves of sweet vernal grass, Antlioxanthum odoratum. 90 BKITISU APHIDES. Tyciiea phaseoli, Pass. Plate CXXVIII, figs. 7, 8. Vii'i parous female. Inch. Millimetres. Size of body 0*0G0 X 0*040 1*52 X l'Ol Length of antennas 0*025 0*63 Large, globose or semi-globose. Opaque white. Slightly pubescent. Head flat and broad. Legs mode- rately long in the second brood, but short in the queen Aphis. The above measurement represents the size of the queen Aphis, which is blind. The brood proceeding from her are of different sizes according to their different conditions of development. The adults have 5-jointed antennas, the fifth joint being rather the longest, and the fourth the shortest. Minute pigmentary spots represent the eyes in the full grown insects. Sometimes this species is numerous at the roots of the scarlet-runner, Phaseolus coccineus, from which the above specimens were taken at Walthamstow. It occurs also upon the French-bean, Phaseolus vulgaris, and also upon the roots of Brassica, Euphorbia, and Amaranthus. Genus XXXIV.— ENDEIS, Koch* MlNENLAUS. Rostrum moderately long. Antennas 5-jointed. The first two and the fourth nearly equal ; the third the longest; the fifth ends with a nail. Eyes very small, but prominent. Body cycloid or else pear- shaped. Cauda obtuse and bristly. Legs very short; tarsi and claws as in Tychea. Koch remarks thai, as far as his knowledge went, his two species, Endeis h, lla and B. rosea, lived in small companies about the roots of wheat in September. * From IvSu'ic, deficient. ENDEIS PELLUCIDA. 91 The proportions of the antennal joints as given above are slightly different from those given by Koch ; but I prefer to group the following three new species under Endeis rather than form another genus out of the somewhat obscure characters furnished by the materials at hand. Endeis formioina, Bucldon. Plate CXXIX,figs. 1 and 3. Viviparous female. Inch. Millimetres. Size of body 0-045x0-040 M4xl'01 Length of antennas 0*01 5 0*38. Opaque white, globose, smooth, somewhat mealy; narrow towards the head. Abdomen ringed. Head with two brown patches on the occiput. Eyes brown and very minute. Antennas with five nearly equal joints. Legs and antennas brown. Rostrum short and stout. Tarsi with two claws. Taken by Mr. James Hardy under the dry stones formed from the porphyritic rocks on the Cheviot. In May they were numerous in the ant-hills under roots of Garex dioica. They mostly affected those nests of Formica umbrina which were located on the dry slopes. Endeis pellucida, Bucldon. Plate OXXIX, figs. 2 and 4. Viviparous female. Inch. Millimetres. Size of body 0-035x0-030 0-88x0-76 Length of antennas 0-015 0-38 Body very broad behind, narrowing to the head ; pale greenish or opaque white ; much ringed, pilose. Head stained reddish. Eyes none. Tail obtuse and 92 BRITISH APHIDES. rounded. Antennas with five nearly equal joints. Legs pale and short. Rostrum stout and short. Taken under tufts of grass, such as Poa annua, covering the nests of ants, and exactly in the same situations as noted in the preceding species. They were found at Beckenham during February. Endeis carnosa, Bucldon. Plate CXXIX, figs. 5 — 8. Endeis bella 9 Koch ? Viviparous female. Inch. Millimetres. Size of body 0-030x0-025 0-76x0-63 Length of antennas 0-010 0-25 Body circular, much domed. Uniformly whitish- yellow, flesh-coloured, or pink. Brown at the tail. Antennas short, with five nearly equal joints and the usual tubercle. With age the third joint lengthens. Head very broad, with a brown dot on the vertex. Eyes very small and brown. Legs exceedingly short, hardly produced beyond the circumference of the body. Cornicles none. Cauda, viewed from under- neath, cylindrical and truncated. Tarsi with two minute claws. The whole insect is finely pilose. On the vertex the hairs are discoid and capitate. Captured in February in an Ant's nest with several other Aphides, including Trama and Paracletus. They had many young wood-lice (Oniscus) in their company. Taken at Beckenham. Genus XXXV.— RHIZOBIUS,* Burm. Rostrum very short, rises between the first coxas. Antennas very short, five-jointed, the first four joints * From /J«£iW, a rootlet; /3u5w, I live. EHIZOBIUS P02E. 98 nearly equal in length. Eyes inconspicuous. Body more or less furnished with woolly flocks. No necta- ries nor tail. Legs short, tarsi terminated by a single claw. Winged forms unknown. Neither males, females, nor true ova have been yet described. Passerini describes Rkizobius menthce and B. sonchi. The latter insect is found at the roots of various plants, as Achillea, Sonchus, Stachys, Galeopsis, and Cichorium. I have not been able to identify these species in England. Passerini makes the antennas six-jointed. The characters, however, are very incon- stant. Rhizobius poj;, Buchton. Plate OXXIX, figs. 9 — 14. Viviparous female. Inch. Millimetres, Size of body 0-075x0-035 1-89 X 0-8! Length of antennas 0-010 0-25 Long oval (in the spring individual fusiform). Colour dull ochreous yellow. Eyes, antennas, legs, and two occipital longitudinal bands, brown. Antennas very short, varying according to age ; from three to five joints and a nail. Abdomen deeply ringed with numerous dark spots, ranged in transverse rows across the dorsum, from which woolly matter sparsely proceeds. A pale line passes from the vertex down the whole back. Eyes very minute. Legs very short ; the coxas being placed well forward on the sternum. The tarsus is armed by a single claw ; but, as this has two bristles, a high magnifying power is necessary to show its single character. Rostrum very short, but this increases in length by age to the third coxas. Yery numerous at the roots of Boa annua on the Northumberland moors. On moving the soil the white tufts of cotton-like fibre, spun from the dorsal pores, betray the presence of these insects. Sometimes 94 BEITISH APHIDES. the Aphides are solitary, at other times small com- panies of eight or nine may be found herding to- gether. They occur from May to October, and then probably they burrow deeper and evade observation. Occasionally the antennal joints differ in number on the two sides, thus development would seem to go on at uneven rates. APHIDES IN THEIR ECONOMICAL RELATIONS TO ANTS. The subject of favouritism amongst insects affords one of the most curious phases of their economy. At the same time the matter is one of the most obscure. It has exercised the imagination and ingenuity of Entomologists for more than two hundred years, and at present hypothesis, more or less probable, is put forward as to how far mere utility or intelligence, or even a quasi-civilisation, has produced such peculiar conditions of life. These habits, which may be styled Sycophancy* or Paracletism,f differ from parasitism ; for one insect does not prey on the other, but is nursed and cherished as a pet. The habit comes out most markedly amongst what may be considered the most intelligent insect- orders, like the Hymenoptera. The wars, raids, slave-driving, huntings, stratagems, and singular architecture of this order has been de- scribed by many, but Sycophancy or, better perhaps, Paracletism would suggest a peculiar refinement beyond mere utility. The handsome apathetic humble-bees are destitute of corbiculas or pollen-baskets, usually developed on the thighs of the Apidje. These large Bombidae apparently neither work or gather honey. Have they become degraded, and have they lost at the same time, by disuse, the natural apparatus conducive to * From o-vKohis genista (rumicis ?) Siphonophora sol'uhujiu is Threpa/nosi/phv/m platanoides Lachnus agilis ( 'hut'tophorus populi an tubes . Spermatic capsules. 7 .. 5 6 .. 3 5 .. 3 6 .. 5 5 .. 3 7 .. 5 4 .. 3 4 a.— THE MALE APHIS AND ITS REPRODUCTIVE ORGANS. The occurrence of this sex amongst Aphides is comparatively rare. Some explanation of this paucity * Balbiani, ' Mem. sur la Generation des Apbides,' p. 5, 1870. I have often seen tbese ligaments in the pseudovaria, but, like Prof. Huxley, I have not met with them in the true ovaria. — G. B. B. MALE ORGANS. 123 perhaps may be found in the fact that the male is polygamous, and will visit many females. The males nevertheless occur in two forms. The winged varieties are large insects, whilst the apterous males are very small, and sometimes so diminutive that they were for a long time overlooked altogether. Kyber's opinion of the non-necessity of the male to perpetuate a cycle doubtless was in a measure formed from a belief in its non-existence. The neces- sity of the male at certain periods, however, would seem now to be proved by this dimorphism. The winged insect is fitted for long flights, and by its visi- tation makes a provision against "in and in " breed- ing ; whilst the influence of the minute apterous insect, which is often incapable of nourishing itself, must be very circumscribed. The winged males of the higher genera of Aphides are often elegantly marked and of bright colour. They are fully-developed insects, provided with large eyes, compound and otherwise, and also with long, well accoutred antennas, to assist them in their roving expeditions. The apterous males also are often brightly coloured ; but in the lower genera, such as Schizoneura, Pem- phigus, and Ohermes, &c, they appear to be little more than animated locomotive sperm-cells. They possess neither eyes nor mouths, they have only rudimentary digestive apparatus, and consequently, after fulfilling their office, they speedily die. The external genital organs of the male Aphis have been well described by Balbiani, and his memoir is elaborately illustrated.* If exception can be taken to his illustrations of Aphis, it may be said that they are too diagrammatic. The figures are symmetrical, and they form elegant drawings ; but the conditions are not such as can be seen immediately, and at one view, under the microscope. * Balbiani, " Generation des Aphides," ' Ann. des Sc. Nat.,' 1869, 15 ser., t. si. 1 2 I BRITISH APHIDES. The original drawings I here offer the reader are perhaps crude, and are not put forth in competition with the more finished work of others. They may have some interest, however, as being almost exclu- sively camera draioings, and as having been produced under a comparatively small amplification (the twelfth of an inch objective not being often resorted to) ; and particular adroitness in dissection will not be required if their verification be desired. The penis is of large relative size in Aphis. It is of a peculiar shape, recurved and enclosed within the cavity of the body, and only exserted during the act of fecundation. A gentle pressure on the abdomen, however, causes the organ to protrude; and when once it has been artificially exserted, it does not appear to return to the body-cavity. It is supported in its action by the embrace of a coriaceous ring and certain plates known as the copulative armature. The act, which requires some time for its completion, is many times repeated ; one male being sufficient for the fecundation of many females. Reaumur and De Geer have given ludicrous accounts of the wooing of the males of the great oak Stoma- phis. Lichtenstein, who has witnessed the operation, says, the males are very ardent. Perhaps the best method for examining the internal generative apparatus of Aphides is to make a clean cut with sharp scissors across the abdomen; and place the portions in water containing a little syrup or glycerine. Under gradual pressure, or by the aid of needles, a group of tubular vessels, variable in number, come into view. These tubes, having more or less pyriform extremities, are the spermatic capsules, converging at their bases into a fasciculus or bundle, which appears to lie under the intestinal canal of the Aphis. There are two fasciculi present, and they unite into one Bingle canal before passing into the penis. These testes seem to float unattached within the liquids of the body-cavity, that is, they are not enclosed TESTES. 125 in any common envelope. The corresponding organs of Aphis jpadi, however, according to the researches of Leuckarb, would seem to vary somewhat from this general type ; and Prof. Balfour points out, also, that there is something abnormal in the female organs of this species. Balbiani states that the form and position of these sperm-capsules vary at different ages of the insect. In the larvae and pupse they appear as elongated sacs ; in the adult they appear shorter and more ovoid. Each capsule is terminated by a short peduncle which, communicating with its corresponding deferent duct, finally unites into a single branch towards the medial line of the body. Just below this point of coalescence there are expansions of the walls of the ducts, which Balbiani thinks are comparable to the vesiculae seminales of other insects. These vesicles descend in the form of two cords and insert themselves close together into the ejaculatory tube. The sperm-capsules have a knotty or tuberculose exterior, and when partly transparent they are highly refractive to light.* The vasa deferentia are lined with epithelial cells, which, however, can only be seen under treatment with acetic acid, and under high magnifying powers. Male Aphides have a single pair of muciparous glands, the secretion from which probably forms a vehicle for the transport of the spermatozoa through the efferent passages. These muciparous glands of Aphis were noticed by Morrens ; but he, like Leon Dufour, mistook their nature, and considered them to be vesiculas seminales. The ejaculatory canal ends at its posterior part in a cul-de-sac or bulb, into which the deferent vessels debouch ; and the other extremity terminates at an orifice in the neighbourhood of two horny valves, forming the copulative armature before alluded to. Balbiani has fully described the curious and highly- * Balbiani, ' Mem. s. 1. Gener, des Aphides,' 1. c, p. 55. 12G BRITISH APHIDES. complicated penis, which is a true intromittent organ. According to his explanation the erection is caused by a regular turning inside out (renverser au dehors), like the finger of a glove. It is caused by a pressure from behind ; and it can be therefore easily made to protrude by artificial squeezing. The penis may easily be seen to be composed of two independent membranous tubes, one within the other. The interior tube is much plicated, and is somewhat of a resistant nature. It shows no direct attachment except through the connections with the deflecting ducts and the accessory glands, the secretions of which pass directly into its cavity. The copulative armature consists mainly of two chitinous valves ; which by their approximation protect and perhaps compress the genital opening. Two pilose mammiliform processes are connected with the semicircular border-plate of the orifice, but their exact import is obscure. Probably they act as compressors.* From the inverting action of the penis it is obvious that the four separate ducts which are attached to its posterior portion are drawn into the inner channel at the moment of its protrusion. The great size of this organ is remarkable. In some cases it equals one third of the length of the animal's body. A notable example of such may be seen in Chcrmcs abietis which I have figured. The sebific glands of the male may be considered, perhaps, homologous to the collctcrial glands of the female. In most male Aphides from three to five sperm- capsules may be counted as ranged in fascicles on each side of the body. In the species Siphonophora millefolii, Drepanosiphv/m platanoides, and Aphis pcr- sicce, each lateral fasciculus contains six capsules; but the number appears to be inconstant in species of * For plates illustrating the above see vol. iv, Plate CXVIII, fig. 8, and Plate G. The principal figure relating to the male organ is copied from Balbiani's Memoir above cited. Some of the smaller details are also drawn from the same source. SPERMATOZOA. 127 the same genus. Siphonophora jacece is thus said to contain ten follicles in all. In masses so tangled, and so liable to injury during dissection, it is not easy to speak very decidedly on this point. Nevertheless, this point of number would have some importance, if Balbiani's views are correct, viz. that there is a close numerical relationship between the sperm-fascicles of the male and the ovarian chambers of the female. Here it may be remarked that, just as germ-masses are visible in the female foetus, so sperm-capsules may be distinguished in the males just after their birth. 4 6.— THE SPERMATOZOA. The sperm-cells of Insects, like those of other animals, are furnished with a vibratile filament, which some have likened to the filament of the vegetable stamen. Notwithstanding the name, these minute bodies are to be looked upon rather as a peculiar product of organic growth within the sperm-capsules, somewhat analogous to the fine moving processes of the ciliated texture, than as distinct organisms.* If a gentle pressure on the abdominal rings of the male Aphis be continued after the protrusion of the penis, a copious escape of minute bodies from the ejaculatory tube will be noted, and these will scatter themselves throughout the weak solution of sugar or albumen used during dissection. Difficulties occur in the examination of these minute cells which constitute the spermatozoa of Aphis. Pure water after a time through endosmosis breaks them up ; but by a judi- cious use of acetic acid or other menstruum, parts other- wise invisible may be brought into view. These cells contain a nucleus and also a nucleolus.* In all cases that I have examined, where the male is adult, these cells have shown only a slight motion, * Dr. Allen Thomson, art. " Ovum," Todd's ' Cyclop, of Anat.' 128 BRITISH APHIDES. more easily described as gyratory, than like that ener- getically displayed by sperm-cells in the higher animals. These spermatozoids have a tendency also to gather into knots. The process of separation of these elements from their capsules is discussed by Balbiani. It does not materially differ from that in other Insects. The before-noted capsules contain numerous cyst- like bodies, composed of a definite membrane enclosing a multitude of minute cells disposed at one end of the cyst, and a bundle of filaments ranged parallel-wise at the other. When the sperm-cells are mature the cysts break up or burst, and the filamented cells dis- entangle, and are then free to move down the vessels into the suitable vesicles. As to the motion of these sperm-cells exterior to their containing vessels and the spermotheca of the female, I will quote the substance of Balbiani's words, which have also reference to the nuclei and nucleoli of these bodies. As I have not possessed the requisite address to exhibit these mere points, which approach the limits of microscopic definition, I may be permitted to do so. " I will add that even when the sperm-cells have attained their independent existence, they have never presented to me (ne ni'ont jamais present e) any trace of spontaneous movement ; but on subjecting them to the action of a weak alkali, which notedly evokes the movements of sperm-cells of other animals, it often provoked feeble contractions ; but these disappear in a short time. It is not, however, uncommon to see the spontaneous movements of the spermatozoa actively executed in the generative organs of the female." Balbiani considers that there is a close analogy between tin- sperm-capsule and the true ovum, and if so, thai ilieiv should be analogically a nutritive mass and a germinal centre in the former. The first is thought by him to be represented by the nucleus MIOROPYLE. 129 known to all histologists ; the second is represented, according to Balbiani, by the still smaller vesicle or globule seen by him as furnished with a filament. This he thinks he has established in the spermatozoid, and it perhaps has been before indicated by Lavalette Saint-George. Prof. Balbiani styles this last point " le vesicule spermatogone," to suggest that it is analogous to the corresponding element placed in the germina- tive focus of the egg, that is to say, in the germinal vesicle.* But there are good reasons for believing that the sperm-capsule is the sole representative of the ovum. The spermatic cells originate from cells indis- tinguishable from the primitive ovum; so that the fusion that takes place (at impregnation) is the fusion of morphologically similar parts in the two sexes. Whatever function may be assigned to the nucleus of the spermatozoon, it would appear that a single head of the same penetrates into the vitelline sub- stance, to seek the homologous body (female 'pro- nucleus). These fuse together, and the result is fertilisation, followed by segmentation of the yolk. The functions of the micropyle in Aphis perhaps are of a double nature. Thus apparently it forms an orifice for the entrance of nutritive matter, and also for the spermatozoa. These functions may coexist. In Pliyl- lajohis fagi the micropyle appears as a distinct lipped orifice ; but in Lachnus longipes the appendage beyond the summit of the ovum leads me to suppose that this part really represents the polar cell or cells of the ovum with its projecting spindle; rather than the simple micropyle. If it be so, the knot of cells at the base of the spindle might well represent the star-shaped body seen by Fol. On the other hand, my figures are not unlike those given by Prof. Huxley as probably con- stituting micropyles.f * Balbiani, • Gen. de Aphides,' p. 82, et seq. f Balfour, ' Treat. Comp. Emb.,' pp. 20, 58, 69 ; also vide my figs. 6> 7, 8, 9, Plate H. \ also Huxley, 1. c, Plate 40. VOL. IV. 9 130 BEITISH APHIDES. II.— BIOLOGY AND MORPHOLOGY OF APHIDES. 1.— GENERAL OBSERVATIONS. It may be said that Aristotle initiated the science of biology, when he detailed the observations con- tained in his Hist. Animalium and in his Be Partlbus. Amongst other things, he made the acute observation that the young cuttle carried its own yolk-sac, for some time after birth, protruding from its mouth ; and that drones apparently were produced from unfer- tilised eggs. As biology may be considered to be the science which comprehends life in all its branches and rela- tions ; so we may severally regard physiology as the science which treats of function, morphology the science which deals with development and form, phytogeny the genealogy of tribes, and ontology the history of germs. In discussing this last section Prof. Haeckel urges that philosophic reflection ought to have equal value with what he calls empiricism, that is, scientific experi- ment. In other terms, that philosophy and experiment should blend.* Much here will depend on the definition we may give to the term "philosophy," in order that * If these threads be blended, they must not be confounded. The caution of some of our early thinkers in separating general laws from hypothesis may be shown by the following remarks of Euler and Laplace. The former says : '• Laws may not be enunciated upon insufficient experience." Thus he shows that *' scr + a t -\-41 up to the 40th term produces a prime number, that is, a number incapable of an exact division by a smaller number. Let a* = any number less than 41 ; then, if multiplied by itself, and added t<> itself, and added to 41, the number is non-divisible; by which it Dlighi be inferred thai ;i law had Keen discovered. Such experience, however, is erroneous ; as the next term so treated gives a divisible number." Laplace says, in introducing his famous theory, " I present this hypothesis with the distrust winch everything ought to inspire that is not a result of observation or of calculation." ANIMAL PEDIGREES. 131 it shall not on one hand mean barren hypothesis, or degenerate into a mere truism on the other. In his numerous investigations, Prof. Haeckel takes up the strong ground, that the germ is an epitomy of the history of descent; or more explicitly, that the forms through which an organism passes from the ovum to development is a compressed representation of the forms through which the ancestors of that organism have passed from its earliest period to the present time. This hypothesis had its origin in the sagacious fore- shadowings of Dollinger and Von Baer. An unbroken succession of animals has been repre- sented by the formula A, B, C, to Z ; but, as links may be lost or unknown in the sequence, the recognised order may in reality be A, B, D, F, to Z. These gaps in the ancestral chain may, however, be theoretically bridged over, through considerations based on com- parative anatomy and embryology, and thus the series might become as A, B, A, D, 0, F. In this way Prof. Balfour shows how these missing links may be shadowed forth by the ontogenic history of B and I) ; and this might lead to a more or less correct repre- sentation of the tribal sequence. Formerly it was believed that all the parts to be found in the adult animal were really included in the embryo ; that they were in a certain manner wrapped together, and that the passage from infancy to age was a real growth ; but a new light appeared in Leu- wenhoeck's important discovery of the spermatozoon. The explanation then offered, however, did not really advance a knowledge of the subject ; or, at least, the general belief then was that each sperm-cell contained the living individual in miniature, and that the ovum merely acted as a nidus for its development. The vast majority, doubtless, are guided and live up to the lights of their age. It is reserved for the re- latively few to shake themselves clear of current prejudices, and by their far-sighted originality to direct 132 BRITISH APHIDES. thought into its true channels. Even the great Leibnitz in his theory of monads leant to the belief that all men were contained in the sperm-cells of the first man. This theory of " encasement " was thought by some to have a certain support from Bonnet's discovery, made about that time, of the parthenogenetic repro- duction of Aphides. A wholly different view, however, was taken by C. F. Wolff, who, following Harvey, and more distantly Aristotle, experimentally showed that there was a true conversion and assimilation of material around a particular spot or germ in the egg; but his explanation met with the greatest opposition; and, indeed, this doctrine of epigenesis was almost ignored by anato- mists for many years after the death of its propounder. Haller strongly opposed this development of organs around the " punctum saliens," and gave his dictum as an unanswerable truth " Nulla est Epigenesis." Wolff, however, may be said to be the father of the theory of development from the germinal layers ; a theory which Pander more fully investigated in 1817, and Von Baer further expanded in 1828. Although the primitive germs of all animals are so similar that the microscope scarcely shows a difference between them, Yon Baer believed that the four great animal groups, Vertebrata, Arthropoda, Mollusca, and Eadiata develop from the egg by processes somewhat different from each other. Nevertheless all recent progress tends to show a fundamental uniformity. The ovum may be regarded as a simple cell which undergoes division and repeated subdivision, so that the segmentation may appear as 2, 4, 8, 1G, or other such portions ; each of which in turn becomes a sepa- rate cell.* These cells differentiate, spread themselves into layers, form membranes, and finally out of these are elaborated the special organs and tissues of the animal body. * See PI. II, figs. 1 to 5, copied from Gegenbaur. GERMINAL LAYERS. 133 This segmentation of the yolk seems to have been first noticed by Swammerdam. The change in the ovum is produced by the action of the sperm-cell or male element upon the ovule with its nucleus or germinal spot. The ovum then becomes fertilised and undergoes remarkable changes in its constitution. The two masses of protoplasm contained in the male and female cells mingle, the nucleus or germ- spot dis- appears, and shortly afterwards the above-mentioned yolk-cleavage commences. The parent cell (cytula) thus becomes of a mulberry-form (" morula " of Haeckel), and then a kind of hollow is formed within the circumference of the cells. This becomes dented inwards at one spot, and somewhat elongated ; by which alteration that which appeared as a single membrane becomes two through the formation of a groove or a cavity with an outlet or blastopore. This constitutes the bilaminar Blastoderm, called also Grastrula by Haeckel because it always comprises the alimentary organs. Thus the first stage of the development of the ovum consists of an accumulation of food-material at one part of the layer, whilst the cells become larger in this part. An invagination or cupping in the wall of the blastopore (Schaf er) occurs ; then the edges of this cup approach, and the opening left forms what Haeckel* considers to be the primitive mouth, or the " blasto- pore " of Prof. Ray Lankester. This invagination, which appears to obtain in all animals above the Protozoa, would seem to occur at the spot where the greatest amount of nourishing cells have accumulated. In this manner two germinal layers are formed; and finally a third layer, which last, however, by some is thought to have a less significance and to arise from the first two. The body-cavity known as the Archenteronf is probably never produced by invagination in the Tra- * BXaoroc, a germ ; nropog, a channel or pore. t apxfi) commencement ; kvnpov, intestine.] 134 BRITISn APHIDES. cheata, though it does so arise in the Crustacea. Prof. Balfour also states that it is very unlikely so to occur in Myriapoda.* Dollinger first used the term Blastodermf, and he early distinguished the three layers under the heads serous, mucous, and vascular. Von Baer studied under Dollinger, and he produced his great work on the evolu- tion of animals during the periods from 1828 to 1837. J The membranes of the germinal disc or blastoderm are known by the under-mentioned terms, and out of them the various organs are elaborated. § Questions are confessedly difficult to answer, as to the complete or partial homology of these layers, and of the organs proceeding from them; and in parti- cular there appears to be uncertainty as to the exact derivative of the sexual organs of animals. In the hydroid polyps, and in the low sponges like Haliphysema, the male and female cells are placed in juxtaposition, and on the same primitive layer, viz. the Entoderm. In many instances amongst higher animals the male organs are derived from the ecto- derm or skin-layer ; whilst the female organs develop from the intestinal layer or entoderm. But yet again there are instances where both the sexual organs seem to arise from the two layers combined. This may be from adaptational causes. Ectoderm ^ Skin, sensory organs, including brain, or fa 1 spinal cord, and nerves. Epiblast ) *■+! (Male sexual organs ?) Mesoderm % Flesh, bones, ligaments. Entoderm ") ^ Nourishing organs, including liver, or [ ^ lungs, and intestines. Hypoblast ) (Female sexual organs ?) || * F. M. Balfour, ' Treatise on Comparative Embryology,' vol. i, p. 451. f UXaoroc and Slpiia, skin, membrane. j Von Baer, ' Entwickelungeschichten dor Thiere.' I Vide Plate H, figs. 13 and 14. |[ As authority for the above grouping, vide M. Balfour, op. cit., vol. i, p. 103 ; and E. Haeckel, op. cit., vol. ii, pp. 3S9 to 401. EGG SEGMENTATION IN APHIS. 135 Thus the rudimentary embryonic form may be roughly likened to a tube the walls of which are four- fold. These layers may be mechanically separated from each other. All animals go thus far through this stage in development ; and the steps have been distinctly traced in the higher Insects, including Aphides. All ova may be grouped under two divisions, dependent on the manner in which the vitelline cells are arranged. The first group is called Telolecithal, in which the yolk when present is concentrated at the "vegetative pole " of the ovum. In the second group, called Centrolecithal, this food-yolk (Dotters Elemente) is concentrated at the centre of the ovum.* The segmentation of Aphis belongs to this latter division. Metschnikoff has shown that in SiphonopTiora rosce the first segmentation-nucleus divides in two, each part of which takes up a position in the clearer peri- pheral protoplasmic layer of the egg. After further subdivision, the nuclei, which are enveloped in proto- plasm, arrange themselves so as to form a peripheral blastoderm composed of columnar cells. f Brandt divides Hemipterous (Homoptera) Insects into two great groups dependent on the differentiation of their respective ova ; but too much stress should not be given to classification on mere segmentation. Homoptera. Without yolk-elements. With yolk-elements, (mit panoistichen Eirohren) (mit meroistichen Eirohren) Psylla, Aphida? foam., Coccus, Aphidce neut. Pediculus. Prof. Moseleyf has recently produced an interesting memoir on the habits and morphology of Peripatus capensis, a Julus-like animal, found under rotten * Balfour, I. c, vol. i, p. 100 ; also see Brandt, ' Ueber das Ei,' p. 48. t Metschnikoff on " Aphis rosae," ' Emb. Stud. Insecten,' Band xvi. Vide my PI. H, fig. 12. t Prof. H. N.Moseley " On Peripatus," 'Phil. Trans.,' 1874, vol. 164, p. 757. 136 BRITISH APHIDES. wood, at the Capo of Good Hope. It has been vari- ously grouped as a Mollusc, an Annelid, and a Myrio- pod. It is now shown to possess a complete tracheal system. This organisation, and the characteristic form of the embryo coiled within the egg, are con- firmatory of the affinities now acknowledged to exist between Annelida, Myriapoda, and Insecta.* Such relations have been before indicated by George New- port; and the illustrations furnished in Prof. Moseley's memoir, and by Prof. Balfour for the Section Proto- tracheata, fully bear this out from their embryonic stages of development. The remark, that " Peripatus points to the connection of the ringed and flat worms, by means of this intermediate step, with the classes only of the Arthropoda — the Myriapods, Spiders, and Insects, i.e. the Tracheata," shows the importance of this animal as a link in the construction of the great zoological tree. Although superficially the hexapod larva of the Centipede has a striking resemblance to some insect larvas, there really is no comparison ; for, even if the legs in the two are thought to be homologous, it is clear by embrijolor/;/ that the insect has sprung from an ancestor with numerous legs, which have become atrophied ; and not from a hexapodous larval form prior to the development of the full number of adult appendages. + The morphology of Aphides has been well studied by many French and German biologists, yet it may be noted that, with the exception of the single memoir by Prof. Huxley already alluded to, the contributions of English authors have been very scanty. It is true that we have a short paper on " The Ovum of Aphis," by George Newport, and incidental remarks on this subject are scattered through the works of Dr. W. B. Carpenter, Dr. Allen Thompson, Prof. Balfour, and a * Balfour, chap, xvii, 'Tracheata,' p. 316. f Balfour, /. c, see note, vol. i, p. 323; also G. Newport, 'Phil. Trans.,' ou " Myriapoda,' 1841. LAWS OF HEEEDITY. 137 few others ; yet only one exhaustive treatise exists in English on this subject. Although open to the charge of telling a thrice-told tale, the author puts forth the following remarks, which embody some of the more recent labours of continental workers ; but they are intended chiefly for the use of those who may not have leisure or inclina- tion to consult such in their original forms. For those who look for pure histology and complete embryology, references may be found in the appended bibliographic list of authors. The science of embryology as it now exists is com- paratively of a recent date. Much of its present value and importance consists in its bearing on phylogeny, or the history of races. It seems now to be a recog- nised truth that the embryos of the higher animals, though not resembling the adult forms of the lower animals, nevertheless show a close similitude to the embryos of the latter. Physiologists are multiplying proofs in this direction almost daily. Prof. Balfour points out that these phenomena have an explanation in the somewhat antagonistic principles of heredity and variation. The first law enunciates that " the characters of an organism at all stages of its existence are reproduced in its descendants at corresponding stages." The second law asserts " that offspring never exactly resemble their parents." By the common action of these two principles, continuous variation from a parent type becomes a possibility, since every acquired variation has a tendency to be inherited. Again, " each organism reproduces the variations inherited from all its ancestors at successive stages in its individual ontogeny, which correspond with those at which the variations appeared in its ancestors."* It will be interesting, therefore, to ask if any and * Prof. F. M. Balfour, 'Treatise on Comparative Embryology,' Introd., vol. i, p. 3. 138 BRITISH APHIDES. what information may be gained by the study of embryonic and larval forms in Aphis ; to watch if any ancient type really shows itself as recurrent in such ; and to learn if any organs, traceable in the larvae, are lost or atrophied in the adult ; such organs having been beforehand persistent in a lower group. Von Siebold, in 1839, carefully investigated the organs of reproduction of Aphis lonicerce, and he con- firmed Dutrochet's discovery of the spermatheca and the colleterial glands of the oviparous female. He described three forms of Aphis lonicerce, viz. the winged male, the winged viviparous female, and the apterous oviparous female, which last insect he showed was the produce of the winged female. The curious reproductive phenomena of these insects led Steenstrup* and other authors to consider the parents not as ordinary females but nurses (Ammen). Some regarded the whole reproductive apparatus as a collection of germinal stalks, and others looked on them as fictitious or false eggs. The arguments for and against have been considered by numerous investiga- tors, and therefore it will not be well here to enter upon the intricacies of so large a subject. On the other hand, Siebold, Owen, Victor, Carus, and Burnett asserted that there was a clear difference between the true ovum and the yolk-mass which appears in the chambers of the larval forms. These last bodies develop without concurrence of any male element. Some denied that they possessed a germinal vesicle. Leydig, Huxley, Brandt, and others state their con- clusions that there is no histological difference between the young organic germ and the true ovum. In 1858 Prof. Huxley discussed the development of the false egg or " pseudovum," and then described, in another genus of Aphis, the ovum or true egg, together with its manner of development from the ovarian chambers. Finally, he compared, in the same paper, the organic and the sexual processes of generation. # Steenstrup, 'Alternation of Generations,' p. 108, &c., Ray Society. DEVELOPMENT OF THE OVUM. 139 He states his views thus : "I look upon it as an established fact, that the primary steps in the agamic development of Aphis are : First, the enlargement of the periplast around one of the pseudovarian vesicles and its detachment as a separate body, which from its resemblance to an ovum I will call a pseudovum. Secondly, the contemporaneous formation of a distinct chamber — the penultimate chamber of the pseudovum. Thirdly, the disappearance of the vesicle of the pseudovum, and the conversion of the latter into a germ-mass composed of cells embedded in intercellular substance.* 2.— DEVELOPMENT OF THE OVUM. The examination of the ova of Aphides after laying is attended with some difficulty, on account of their dense and highly coloured shells. Usually when first excluded these tough membranes are pale and yellowish, but they speedily become brown or black; a change which com- monly takes place after impregnation. No light passes through them in this condition, but a treatment with olive oil would seem to render them less opaque, and if precautions be taken the maceration is not neces- sarily attended by the death of the egg.f However, some of the changes within are much more readily studied before than after extrusion from the ovaries. I have made many dissections of Aphides for my own satisfaction, and some of the drawings I ven- ture to place before the reader in Plates H and I. Notwithstanding their simplicity they may not only give confirmatory evidence, but here and there per- chance suggest something of interest to the practised morphological eye. The letterpress in connection with these plates will * T. H. Huxley, "Morphology of Aphis," 'Trans. Linn. Soc.,' vol. xxiii, p. 201. 1 f Balbiani, ' Mem. d. Gen. des Aph.' 140 BRITISH APHIDES. supply sufficient information to the general reader to carry him through the series. Ocular proof is easy to be obtained microscopically, that the ovum and the pseudovum arise from organs essentially similar. What has been before said of the pseudovarium may, in almost the same terms, be also said of the ovarium. The ovarian chamber has a translucent terminal ca3cum, within which eight or more nucleated movable masses are disseminated. These eventually pass down into the constriction which occurs below, and probably through or by means of the yolk-cord discovered by Huxley, and more recently noted by Brandt. In passing the spermatheca (which does not occur in the viviparous female) the ova meet with the issuing spermatozoa ; or, as segmentation may be seen in the eggs before they descend into the ovaries, it is possible that the sperm- cells travel into the chamber above, just before the egg makes its descent and issue. The body of the ovum is filled by a mass of active living protoplasm, which exerts its influence on tho food-yolk about it. The yolk-cells often congregate more densely at the poles of the ovum, whilst tho germinal vesicle, which is situated at the other end, is freer from the same. The germinal spot usually occu- pies the centre of the egg ; but, as the last matures, it travels towards the side, where important changes set in which are attendant upon fertilisation. The division of the blastoderm into membranes so as to form a kind of loop has been already alluded to. If the edges of this loop or protostome do not close, only one opening is formed in the ectoderm ; but if otherwise, two openings arise, and these form the apertures of the alimentary canal. The localisation of function is carried on by cells segregating or separating for definite ends. Somo cells organise themselves for reproduction, others for nutrition, and others for the production of scales, wool, skin, and the like. POLAR CELLS OF OVUM. 141 The reproductive organs are a development from the hypoblastic membrane or entoderm. A description of the gradual evolution of these organs is far above the scope of this Monograph : the subject is of a nature too special ; and, moreover, it has been adequately treated by others whose memoirs may be advantageously studied in detail. Relative to the development of the ovum in Aphis much interesting information (by way of analogy) may be gathered from Prof. Schafer's article on ova in the ' Quart. Journ. Microscopical Science,' and also from another article, in the same number, by Prof. Balfour on development of the Araneina. 3.-SEX IN APHIS. The significance of the polar cells in the ovum is not certainly known. They occur in the unimpregnated egg, and they result from and are coexistent with the breaking up of the germinal vesicle, parts being appa- rently extruded from the ovum. After the formation of the polar cells, it would appear that impregnation only will develop the egg, but possibly before their occurrence parthenogenesis might occur. The evils of self-fertilisation, viz. the want of suffi- cient differentiation in the sexual elements, would apply with far greater force to cases of partheno- genesis ; and it has been suggested by Prof. Balfour that this evil is prevented by this very function of forming polar cells.* Although Biitschi was unable to see any polar cells in the pseudova of the viviparous Aphis, they may be certainly brought into view by due precaution. Yon Siebold's investigations led him to believe that the eggs bring from the ovary the capacity of differen- tiating themselves into living male individuals; and that the same eggs can be changed as to their proper- * Balfour, ' Treat. Comp. Embryol.' 142 BRITISH APHIDES. ties by the influence of the male sperm-elements, and proceed to develop as females.* Mr. Darwin suggests that the union of individuals has the effect of fusing two life-experiences in the pro- geny, which thus obtains other and wider tendencies and impulses. Thus self-impregnation and partheno- genesis would have to yield to the more active and developing process of di-genesis, that is to say, of the concurrence of two individuals. E. Witlaczil f has recently made observations on the general reproductive anatomy of Aphides. In the same paper he describes the fat secreting body, which is largely developed in the abdomen of these insects. It has been before noted by me that the oil globules, secreted as minute drops from the above tissue,' take various tints, such as pink, green, yellow, or red ; and that the coloration of certain species of Aphis is due to their presence. The above-mentioned author discusses the muscular system of these insects, and he divides the same into a motor and respiratory grouping ; such being respec- tively distributed cither to various parts of the abdo- men or to the tracheae and the stigmata. The cephalic ganglia arc connected with the eyes, antennae, and oesophagus ; and marks are made in the memoir on the pits in the antenna?, which are here referred, not to organs connected with hearing, but to those of smelling. The antennae would seem to serve, he thinks, not so much for finding the female as for discovering suitable food. "O The wax-glands (silk ?) which I have before des- cribed as present in Chermcs dbietis (vide vol. i, PI. C, fig. 6) he finds also to be present in Pemphigus bur- sarins. This species has four on the pro-thorax, six on the meso- ;md meta-thorax and the first six * Von Siebold, ' Comp. Anat.,' transl. by Dr. Burnett. Also vide ' Nature.' October 24th, 1872, p. 523 ; notes by Prof. E. Ray Lankester. f E. "Withicz.il, ' Arbeit. Zool. Ins. Wien,' iv (1882), pp. 397—441 (2 pis). Abstract, ' Quart. Journ. Mic. Sc.,' ser. 2, vol. iii, p. 40. SEX IN APHIS. 143 abdominal rings, four on the seventh, and none on the remaining rings. The development of these wax organs on the backs and sides are said to be correlated with the abortion of the nectaries ; yet, as the honey- tubes never exceed two in number, the above relation is not clear. The reader is referred to this memoir for the author's views as to the origin of the setae of the pro- boscis and their relation to the rudiments of the man- dibles and maxillae. These points have been generally discussed by others in the case of Hemiptera. Like myself, M. Witlaczil was unable to make out the walls of a dorsal vessel. I have, however, repeatedly noted in some transparent species an alternating and pul- sating action down the dorsal regions. Germinal vesicles were, on many occasions, distinctly visible to M. Witlaczil, and he states that the formation of the blastoderm proceeds from behind forwards, and that the cleavage is essentially equal. In adverting to the questions on Phylogeny, glanced at in the Introduction to my third volume, and touched upon at page 134, &c, of this volume, it must be con- fessed that the details now offered are more of a suggestive than a conclusive character. The high antiquity of the family Aphididae, and the fact that the fossil forms very closely resemble those of recent genera, render it difficult to indicate with any sureness the passage of Aphis out of any lower type of Insect. The general reader, perhaps, will agree that in a monograph which is chiefly systematic, so large a subject as Reproductive phenomena should be but lightly touched upon. In the meagre sketch now offered I have freely used the writings of Profs. Huxley and Balfour. When I employ almost their identical words, it is from the feeling that any attempt on my part to recast them would be a loss to the reader, 144 INTRODUCTORY NOTES ON THE ANTIQUITY OF THE HEMIPTERA, AND TAETICULABLX WITH EEOAKD TO TIIE APIIIDINiE AS REPRESENTED IN THE SEDIMENTARY ROCKS AND IN AMBER. Although it will be out of place here to discuss the sequence of insect life in primaeval times, for such a discussion belongs to the province of Geology, yet the Entomologist who has a particular group under study will be interested in comparing the older with the more recent representatives of that group. Accordingly, a few remarks may be permitted as to the first ascertained occurrence in geological times of the Aphidinas. Perhaps the most ancient insect yet discovered is Xenoimira antiquorum, a fly of the Devonian age, with very long wings reticulated somewhat like those of a cricket. Highly differentiated as this insect was at such an early date, we must suppose that numerous other complex forms existed long previous to it, and there seems to be good reason for inferring, so far as America is concerned, that insects were living far back in Silurian times. Later on, amongst the Coal-measures and their con- tiguous strata, we find various marsh-inhabiting beetles and forms allied to the Curculionidos and Buprestida?. These remains occur in situations favorable to the growth of large Equiseta and Calamites. Professor 0. Heer discovered in the Carboniferous FOSSIL CORIACEOUS AND MEMBRANOUS WINGS. 145 beds at Erbignon in Switzerland, a fine cockroach, which he considered to be one of the most ancient animals of that country. He figures the wings, and names this insect Blatta helvetica. It must have been quite two inches long, excluding the antennae. Numerous Ter- mites, and species belonging to the Orthoptera, were also denizens of those coal forests and swamps.* The Hemiptera are nearly as ancient as the Coleo- ptera, and apparently they take precedence of the Di- ptera, Hymenoptera and Lepidoptera. The family types of insects are of vast antiquity, and, what is not a little remarkable, all the remains of the Arthropoda, hitherto discovered, have been referable to existing orders. Yet, from Mr. Darwin we learn that " from the continued tendency to divergence, the more ancient a form is the more generally it differs from those now living." This persistence of type in insects, it must be admitted, does not furnish much direct evidence in support of the theory of evolution of the higher insects from lower forms. The oldest insects on record were highly specialised, and in their organisation show no inferiority to their modern representatives.! In a letter addressed to me, March, 1882, by Mr. S. Scudder, he states that he " has now clear evidence of the presence of the Heteropterous division of the Hemiptera in America, in beds credited with being Carboniferous. Certainly they are not younger than the Permian period." It has been thought probable that the Homoptera, which are less developed insects than the Heteroptera, would have preceded the latter in time ; yet the occur- rence of the latter at the earlier date as shown by fossils would lead to the idea that the coriaceous wing w r as an elaboration from the simpler membranous wing. Although the oldest known Coleoptera and Dycteop- tera possessed horny elytra, it cannot thus be proved * ' Die Urwelt der Scliweiz,' Prof. Oswald Heer, trans, by W. S Dallas, 1876, vol. i, p. 20. f ' Geolog. Antiquity of Insects,' H. Goss, 1880, p. 4. VOL. IV. 10 146 BRITISn APHIDES. that the earliest insects did not possess wings com- posed of simple membranes. Mr. S. H. Scudder comes to the conclusion that the front and hind wings of Palaeozoic Insects were similar ; and that membranous heterogenity made its appearance in Mesozoic times.* Our ignorance of the steps in a natural process need be no barrier to an hypothesis, if it be supported on reasonable evidence, or even analogy. Whether che- mical and other forces were more active in geological times may be a point for discussion. Life under ex- citement is usually intensified, but perhaps at the cost of duration. Under extreme surroundings we mio-ht suppose intermediate links quickly filled up; or at that distant period they might overlap and produce modifications too rapid, for us to follow. Time doubt- less is an important factor, and we are liable to consider an event marvellous or otherwise in proportion to the time consumed in its production or disclosure. For instance, the effects involved in the alteration in brilliance of one whole magnitude of a well-known star in our system, in the course of two days and a half, might appear to us little short of miraculous, if we could so live as to see them. The fragmentary condition in which fossil insects are commonly found renders their examination difficult. Several Continental observers have done good work in this direction ; but the investigations in England are comparatively scanty. To Mr. H. Goss's papersf on " Fossil Entomology" I am indebted for many details ; and also to Mr. S. H. Scudder for his numerous memoirs on the fossil insects of America. Professor Hacckel, with his usual bold stroke of hypothesis, supposes that the very ancient Zoopoda have been the ancestral forms of the Crustacea, and that * « Early Typos of Insects,' Samuel H. Scudder, 1879, p. 21. N.B.— Mr. Scudder has pointed out to me that in my introductory remarks in vol. iii on the antiquity of insects I Lave not given sufficient antiquity (<> the Homoptera. I am glad to be corrected by so able an authority. f " Introductory Papers on Fossil Entomology," by H. Goss, 'Ent. Mon. Mag.,' vol. xv, p. 52, rt acq. P. B. BEODIE ON FOSSIL APHIDES. 147 in later times they developed tracheae (Prototracheata), and that in this manner they became capable of air respiration. They would thus shadow out the Arthro- poda, and thus far the Insecta. Dr. Friz Midler also looks to the Crustacea as a channel through which the Insecta may have risen. On the other hand, Professor Balfour places Crus- tacea in order after Insecta in his ' Comparative Em- bryology.'* Certain it is that insects, with their com- paratively high condition of intelligence, appeared long before the epoch of the great Saurians, and afterwards we find them contemporaneous with the Pterodactyl of the Lias. Mr. A. R. Wallace remarks : — "At this remote epoch the chief families of insects, as set forth by Linnsean genera, were perfectly differentiated and recognisable." The earliest notice of any fossil Aphis that I have met with is that furnished by J. Curtis, who, in 1829, catalogued, but did not figure, " an Aphis of the middle size," forming one of his specimens (No. 25) taken from the Eocene Beds of Aix (Ligurian). This notice occurs in a joint paper by Murchison andLyell. It describes many insects taken from these Tertiary deposits. Curtis says of these specimens : — " Although there are sufficient characters preserved to determine with certainty the genera to which many of the insects belong, the parts which would best do so are indis- tinct, the antennae, tarsi, and trophi being generally very obscure and distorted. f In the year 1839 the Rev. P. B. Brodie gave a short description of some English fossil Homoptera. After- wards, in 1845, he published his book on the ■ Fossil Insects of the Secondary Rocks of England,' to which Professor Westwood added an Introduction and descrip- tions. In this work (now difficult to be procured) Mr. Brodie first notices numerous insects preserved in * See F. M. Balfour " On the Affinities of Peripaius capensis with the Tracheate Arthropoda," ' Comp. Embryology,' vol. i, p. 316. f ' Edinb. New Phil. Journ.,' pp. 287—294, 1829. 148 BRITISH APHIDES. the Wealden [Purbeck] Beds of Wilts, in the Vale of Ward our. At another time he referred to similar forms taken from the Purbeck Beds in the neighbourhood of Swindon, Wiltshire. Remains of the insects, which were found in plenty, comprised examples of Coleo- ptera,. Trichoptera, Diptera, many Hemiptera, and one Libellula. In 1845 the Rev. F. W. Hope described several insects discovered at Aix, in Provence, and amongst these he shortly noted a specimen (marked No. 85) " as a mass of insects resembling Aphidse."* About this time Dr. Mantell indicated the occurrence of numerous insects in the stone quarries of Hartwell, Bucks, and also very similar remains in the shales near Tunbridge and Maidstone. These fragments chiefly consisted of Coleoptera, but I find no Homoptera mentioned in his list. In the above-cited work of Mr. Brodie, figures are given of seventy-four species of insects, selected from 239 specimens found in the Wealden [Purbeck]. The insect limestone of Wainlode (Rhastic), which is about one foot thick, furnished him with many well-preserved examples. Of all these, three only can be fairly referred to Aphis, and of them only one (No. 6) can be considered as undoubtedly belonging to that family. It is named by Brodie Aphis valdensis, and I have figured the speci- men, PI. CXXXII, figs. 4 and 5. The veining of the only wing preserved, at the side of the fossil, is well marked ; and it sufficiently characterises the genus. Nos. 6, 9, and 10 of the same list are named by Brodie Aphis 'plana and A. dubia, but the remains are too fragmentary for useful identification of the species. f Many of these fossil species are of microscopic dimensions ; and Mr. Brodie calls attention to the fact that the greater part of the insect remains which ho found, both in the Lias [Rha)tic] and the Wealden [Purbeck], are of a "most diminutive character." * ' Trans. Ent. Soc. Lond.,' p. 252, vol. iv, 18-15. f ' Fossil Insects of Secondary Rocks of England,' pp. 33—120, 1839. FOSSIL HEMIPTERA OF THE LIAS. 149 Professor J. W. Westwood believed that most of these insects were aquatic in habit, and that they affected the neighbourhood of fresh- water streams, over which they hovered during life and became sub- merged after death. The last author remarks : — " It is scarcely to be supposed that a state of things could have existed in which we should find such a collection of insects as the Wealden [Purbeck] series exhibits, without there being parts of the world inhabited by giant Cicada?, immense beetles, locusts, and grasshoppers, with wings expand- ing little less than a foot, and other insects of the size at least of those of the present creation."* Elsewhere he says : — >" It is not an invariable rule ; but climates of low temperature produce insect forms of small dimensions. The presence of Aphides in the Wealden beds leads to the supposition that the exist- ing climate was that of a warm temperature rather than that of a subtropical character." Discoveries of fossil Aphides have hitherto been comparatively rare, and perhaps the reasons are not difficult to find. Independently of the delicacy of their structure and their minuteness, the circumstance that a mild and temperate climate seems necessary to their existence must limit their horizon, and also the area possible for their preservation. In present times, as a rule, under tropical heats Cicadidee and Fulgoridse take the places of Aphididse. Again, it is pretty obvious that those Aphides inhabit- ing swamps and the banks surrounding still waters were the most suited for preservation. The finest muds and sediments are requisite to yield obvious impres- sions, and moreover sucli sediments must be very rapidly deposited to prevent the disintegration of frail insects. Accordingly we find that the fresh-water beds of (Eningen, within the valley of the Rhine, and the basins of the ancient lakes of Florissant in America, are the localities which up to the present time have * ' Quart. Journ. Geol. Soc. Lond.,' vol. i, p. 400, 1845. 3 50 BHITISH APHIDES. furnished the geologist with the finest specimens of extinct Aphides and allied insects. There are, however, other sources which yield evi- dences of the existence of Aphides in ages long past. The fossil resin known as amber has been studied by Hope, Menge, Germar, Berendt, Goeppert, and others ; and within the masses well-marked genera of insects, closely related to recent ones, are clearly indicated. In the Permian and Trias formations comparatively few fossil insects have been hitherto traced. Professor Heer noticed but one Orthopterous, three Nenro- pterons, and three Coleopterous forms. On the other hand, the insects of the Lias are very abundant. Previous to the examination of the Lias beds of Schambelen, in the Canton of the Argau in Switzerland, only fifty-six species had been described ; but Heer obtained later about 2000 specimens, which he referred to 143 species. Of these the Coleoptera were by far the most frequent; for they numbered 116 species. After them came the Hemiptera, which comprised twelve species of numerous individuals. A well- preserved portion of a wing, showing characters very similar to those of an ant, proves the occurrence of Hymenoptera in these early times. Most of these insects are figured in ' Die Urwelt der Schweiz ; ' but I will only specially allude to the Hemi- ptera, as being the order more immediately connected with my present subject. The ancient Hemiptera in great part appear to have had sanguinary habits, for such we may infer from the construction of their suctorial rostra, formed for drawing blood and extracting the juices of insects. Eight species are mentioned as obtained from tho Liassic marls situated about half way between Zurich and Basle. Two of them are figured. One, viz. Protocoris insights, is about half an inch long, and very decidedly shows its Hemipterous characters. We may remark that the English fossil Hemiptera were certainly not larger than our existing species. APHIDES IN EOCENE BEDS. 151 We may gather from the occurrence of numerous termites, cockroaches, and buprestidous beetles, that the climate, if not tropical, was above what we know as temperate. We do not see Aphis represented ; and perhaps the climate, which here yielded forests of gigantic cycads and tree-ferns, might preclude this family. It is, nevertheless, true that many cycads and conifers appertaining to a hot climate penetrated into Purbeck- Wealden times; and there is unmistakable evidence that Aphis then existed. We find also that fossil plants belonging to the Cretaceous series extended into the Eocene of Switzerland, of Saxony, and of Moravia. Several large pines and firs of a similar type have been found likewise in the Greensand and Gault of England. Fine specimens of such trees, the stumps of which yet remain in situ, are still to be seen on the south-west of the Isle of Wight. As these trees indicate the existence of a cooler climate, there seems to be no reason why we may not yet find remains of Aphides in some of the finely- grained strata and deposits of this district. The finely-textured marine muds which formed some sediments of the Chalk-series would have been well suited to yield impressions of insects, yet only a few beetles have as yet come under observation ; and these must have been entombed in the neighbourhood of some ancient shore-line. Ear north, in early times Greenland showed a mild and genial climate, yielding good examples of several species of conifer (sequoia), poplar, and walnut. As yet, however, no traces of insects have come to light, though there seems to be no good cause for doubting that Aphides, like other winged insects, may have been wafted over on the wings of the wind, and have delighted the taste of the northern ants during the protracted days of Arctic summer. Insects abounded in the localities inhabited by the Pala? other ium, the Anoplotherium, the pig-like Hyopo- 1-jL* URIT1SH APHIDES. tamus, and the graceful, deer-like Xiphodon. In the Eocene beds of Central Europe cercopithecoid mon- keys roved the trees, and bats also flitted after nocturnal insects. The Eocene formations of both the old and the new- world furnish abundant testimony to the existence of several genera of Aphidina3. Where the fossil conifers abound the Lachnince are chiefly represented; the deciduous trees mostly give examples of Aphis proper. In Britain, probably the climate of what is now Alum Bay in the Isle of Wight did not greatly differ from that of the Eocene of Central Europe. At this early time Aralia, Sequoia, Carsia, and Quercus ilex flourished. Prof. Heer likens such a flora to that of the marls of Monte Bolca, near Verona, where the myrtles and sandalwood trees gradually replace the more tropical ferns and plants of an Indo- Australian type.* Briefly I pass over the insects obtained from the Eocene beds of England, such as the Coleo- ptera of Corfe, in Dorset, and those repeatedly brought to light from the limestone of Gurnet Bay (Bembridge series), in the Isle of Wight, as no notices have been published of the occurrence of Aphides amongst them. Mr. Goss says " that there can be little doubt that the Insecta were then abundantly represented, and their rarity as fossils in the Eocene formations of Great Britain can only be accounted for on the assumption that the conditions under which they were deposited must have been generally un- favorable to their preservation. "f Although the Miocene beds of Badoboj, in Croatia, were not fully investigated till Prof. 0. Heer com- menced their study, Dr. J. Unger had described and figured sundry of their well-preserved fossil insects in 1839. They consisted of Diptera, Coleoptera, " Rhynchota, and Hemiptera." I cannot find, how- ever, any trace of Aphides described in his memoirs. * Prof. O. Heer, ' The Primeval World,' vol. i, p. 281. f H. Goss, ' The Geol. Autiq. of Insects/ p. 37. APHIDES IN THE LOWER MIOCENE. 153 There are, nevertheless, many indirect indications of the presence of Aphides in early Miocene times. Then the gad-fly was present to scare the Ki^-parion gracile, the representative of our modern horse ; and bright aphidivorous Syrphida3 glanced and hovered in the sunny glades of those forests, just as they do now with us. There are also evidences of the existence of many plants through the presence of such insects as are believed to confine themselves to particular kinds of vegetable food. From insects obtained from the Swiss Miocene, the occurrence of such genera as Myosotis, Pubus, Echium, Carduus, Trifolium, and others may be inferred. All these plants now afford food for special Aphides, and they may have done so then. With reference to this period, Prof. Heer says some insects climbed to the summits of trees, as with us, to obtain honey-dew from the colonies of Aphides settled there. . . . Great Cicadas hid themselves in the dense canopy of leaves, and filled the air with their monotonous chirping. . . . Gigantic water-beetles, and Hemiptera of different genera, by their presence give weight to the probability that the climate of (Eningen was in late Miocene times of a warm, tem- perate, or possibly of a semi-tropical description. He suggests that at this period a broad arm of the sea passed from the Rhone Valley through Berne, (Eningen, and Vienna ; and thence it widened out as it stretched towards Belgrade and the Euxine Sea. Fresh-water rivers poured their contents into the basins of (Eningen and Pacloboj, the water being more or less loaded with the remains of the animals then living in these districts. Probably in Miocene times the tract now occupied by the Baltic was dry land. This district is the father- land of much of the amber of commerce, fine speci- mens of which adorn the museums of Koniofsberof, Danzig, and Berlin. The Aphides entombed in these masses of fossil resin show the antiquity of the family, and its early appearance in Northern Europe. 154 BRITISH APHIDES. The alternation of marine and fresh-water forma- tions frequently to be observed in these places is generally ascribed by geologists to corresponding upheavals and depressions of the existing sea-bottoms. Thus irruptions of the sea seem to have been frequent, and caused the intermingling of land and marine remains. Seals, sea-mollusks, and sharks may be from such causes closely located with trunks of trees, lizards, Aphides, and leaves of land plants. In the Lower Miocene beds insects are numerous, but examples of Hemiptera at present discovered are comparatively few. Though Aphides have not yet shown themselves amongst these sediments, the Aphis- feeding Syrphidae and Ooccinellidaa would indicate that they were contemporaneous with other Rhynchota. The marls of Radoboj, in Croatia, which belong to the Middle Miocene, possess much interest; for they contain many fine impressions of Aphides ; and as we ascend to the Upper Miocene, specimens become much more plentiful ; and thus we come to the famous insect beds of CEningen. These calcareous deposits formed the floor of a considerable fresh- water lake tying in the Rhine Valley between Constance and Schaffhausen. The sediment has been very favorable to the preser- vation of insects, the casts from their wings being in many cases very perfect. Even midges, with the hairs on their antennaa and legs, are clearly recog- nisable under the microscope. This will show how swiftly the insects must have been submerged and covered by mud before there was time for their decomposition. This mass of insect remains occurs in an exceedingly fine-grained limestone, scarcely exceeding an inch in thickness. The stratum is so laminated that it may be cleaved into about 250 paper-like slabs, of such delicacy that even the original colours of the insects may sometimes be seen, as if they had been painted on the matrix. Upwards of 5700 specimens have been examined APHIDES AT FLORISSANT IN COLORADO. 155 from the Swiss Miocene, from which 876 species of insects have been deduced : 844 of these occur at CEningen. Coleoptera are by far the most abundantly represented, but still the Hemiptera number as many as 136 species.* Apterous insects, as a rule, are more rare than winged. Probably they were less drifted by winds, and but little liable to drowning in the shallow waters. Thus, winged ants are in profusion ; some having been killed with their wings yet expanded, whilst the apterous forms are infrequent. It is not improbable that some deleterious gaseous exhalations suddenly passed over these waters. Destruction was so rapid that several examples occur in which males and females remain conjugated; and now they rest together in their silent tombs. t The presence of larvaa shows that insect metamorphosis occurred then, much as it obtains now. Although the climate of Miocene times here must have been at least as warm as that of Southern Italy, Aphides disported themselves side by side with large Cicadidee and gigantic water-bugs. Mr. Walker thought that if Aphides exist in tropical climates, they will probably be found to be entirely viviparous, and then there will be no necessity for the egg. But the fact that Aphidian ova are quite as common in the South of France and Italy as in Britain proves that mere temperature has but little to do with the appearance of the true sexes and their issue. Several fine examples of Aphis, of Lachnus, and of Pemphigus have been figured by Prof. Heer, some of which I have reproduced in Plate CXXXIL A gall-making Pemphigus clearly attacked the leaves of an ancient kind of poplar tree, and in a manner very similar to that to be observed on our own, and it made the like excrescences. * ' Primaeval World,' vol. i, p. 296, et seq. f ' Priru. World,' vol. ii, p. 44. 156 BRITISH APHIDES. Recent researches have proved that both the Heteropterous and Homopterous Hemiptera, includ- ing Aphidida?, are well represented in North America by fossil remains. Many specimens have been obtained from the districts of White River in Utah, and of Green River Station in Wyoming. The remarkable lacustrine beds of Florissant, in Colorado, arc now undergoing a thorough examination by Mr. S. H. Scudder, who has already thrown so much new light on fossil insects. The last gentleman gathers from the description of the fauna and flora (which is very abundant) that the remains belong to later Miocene time, and therefore they may prove interesting as sup- plementing Prof. Heer's labour in Europe. Mr. S. H. Scudder kindly enables me to reproduce several of his fine figures of Aphides — figures which are prepared to illustrate his works on the Fossil Insects of North America, in connection with the Geological Survey of the United States. These plates have not yet been published, but I have his permission to use them, and some figures are redrawn in PL CXXXIII, Vol. iv, of this Monograph. The ancient lake at Florissant is situated high up in the mountains on the southern slopes of the Colorado Range. The existing basin is about five miles in diameter, but several creeks in former times ran up from the shallow water into the neighbouring valleys. These Tertiary beds form the bottom of a basin which overlies the granite. Here and there this rock protrudes from the flat in the form of islets. The superincumbent beds comprise conglomerates and variously coloured sandstones, interposed with deposits of fine smooth, argillaceous material, well suited to the preservation of leaves and insects. Below these beds, black, brown, and whitish-drab shales occur, containing large masses of opalised wood, probably the remnants of ancient Sequoia-. Some of the stems still remain in the positions in APHIDES OP FLORISSANT. 157 which they grew; and within present memories they had a size from five to six metres (diameter?). Specimen- hunters have now greatly injured these fine fossil examples.* Trachytic rocks, lavas, and remnants of old geysers, are in the immediate neighbourhood. These last are indicated by deep and polished funnel-holes sufficiently large to conceal a man, and their presence shows that formerly volcanic energy was periodically exerted over a considerable district. The most prolific insect beds of Florissant appear to be the drab-coloured shales above indicated, of about sixty centimetres thick (=23 - 6 inches), the chemical constitution of which has been investigated by Dr. M. "Wadsworth, of Cambridge, Mass. He is of the opinion that clouds of volcanic ashes must have fallen into a still lake. Perhaps a"moya" or a mud-flow "may have been worked over by water, covering the under- lying beds and entombing the interesting remains now brought to light. The matrix is described as "a grey mass containing fragments of feldspar, augite, &c, cemented by a fine earthy ground-mass." These beds are wonderfully prolific in fossils, and in this respect they even outstrip the famous deposits of (Eningen. Mr. S. H. Scudder has already described 250 species, and thinks that probably at least 1000 more may be separated from the rich masses obtained from Florissant. Hemiptera form about 11 per cent, out of the whole order Insecta, and they are nearly in the same pro- portion as those which occur at (Eningen. Mr. S. H. Scudder thinks, however, that the fauna of his district more nearly approaches that of Radoboj ; for 40 per cent, is represented by Hymenoptera at Floris- sant ; against 14 per cent, only at (Eningen. On the other hand, as at Radoboj, ants are largely preserved; as many as 4000 specimens have been examined, yielding to Mr. Scudder no less than fifty separate species. * ' Bull. Geol. Surv.,' vol. vi, p. 284, S. H. Scudder. 158 BRITISH APHIDES. "We may pretty safely infer that many of these ants visited their favourite Aphides. Just as in Switzer- land, these American Miocene times furnished large carnivorous Syrphidas, the coloured patterns on whose bodies and broad abdominal bands, are still clearly recognisable. From some unknown cause the Homoptera are better preserved in these deposits than the Heteroptera. Aphides are common, and include probably eight species,* all Aphidince, excepting a few referable to Schizoneurinse. The details are amply sufficient to decide the family or genera to which they ought to be referred ; indeed, these specimens seem to be the most perfect of all fossil Aphides yet discovered. The same paucity of larvos, of all sorts, to be noted in the (Eningen beds, here also obtains. Almost all the American examples of Aphides yet figured are winged; and this leads to the supposition that large flying swarms may have been suddenly entangled in a volcanic mud shower, or in the downpour of some neighbouring geyser, which mud, after precipitation into the lake, carried them to the bottom, before decomposition of their delicate texture. Lachnus is duly represented; and appositely amongst the flora of this period we find such usual food plants as Pinus, Juglans, Quercus, Carpinus, Betulus, Alnus, Salix, and the like. There seems to be every probability that the waters of this lake were fresh ; and both Mr. Lesquereux and Mr. S. H. Scudder infer from the general fauna and flora of Florissant that formerly a warm climate, like that of modern Southern Italy, prevailed. Some doubts arc expressed by Mr. S. H. Scudderf as to the exact age of these beds ; but the most competent authorities seem to come to the conclusion that if they are not so old as the early Miocene, they must be placed in the middle section of that scries. No safe • Ibid., p. 293—293. t Vide S. H. Scudder, /. c, p. 300. APHIDES OF FLORISSANT. 159 and certain conclusions as to their age can be made from the evidence alone of the entombed insects. Mr. S. H. Scudder thinks that some revision of the CEninsfen and Radoboj insects must be made before a good comparison can be of value between the two continents as to age. It is remarkable that no certain traces of insects have yet been noted in beds of the Pliocene period ; and this paucity of insects also in the Quaternary or Post-Tertiary superficial deposits is equally noticeable. Possibly the nature of the deposits in these compara- tively recent times were unfavorable to their preserva- tion, as has been suggested by Goss and others. Remains of Coleoptera, chiefly elytra, have been found in peat-beds, and in brick-earth in several parts of Great Britain, Switzerland,* and North America ; but the Hemiptera do not seem to have left their remains in such a condition as will allow of their identification. The Glacial and Drift periods appear to have been ill adapted for the preservation of insects. Probably the lower temperatures of the epoch just before the appearance of man on the earth were inimical to such. With the exception of a few beetles it is believed that no fossil insects have been described. * Prof. Heer, < Der Urwelt,' 1865, p. 481, &c. 160 BRITISH APHIDES. l.-ON THE ANTIQUITY OF APHIDES AS EXEMPLIFIED BY THEIR REMAINS IN AMBER. The occurrence of insects, twigs, fruits, seeds, and other organic remains in amber has been remarked from very early times. But although the old Greeks knew the resinous substance that forms the matrix, and surrounds these small beings of ancient days, they chiefly prized this material, known by them as electron, on account of the many hidden virtues supposed to reside in it. Buffon singularly regarded amber as hardened honey; Pliny, however, had more acutely suspected its truer vegetable origin. He says* : — " Nascitur autem de fluente medulla pinei generis arboribus, ut gummi in cerasis, resina pinis. Erumpit humoris abundantia, den- saturrigore vel tempore autumnali. . . . Archelaus, qui regnavit in Cappadocia, illinc pineo cortice inhre- rente tradit advehi rude. . . . Liquidum primo distil- lare argumento sunt qusedam intus translucentia ut formica3, aut culices, lacertseque, quas adha3sisse musteo non est dubium ut inclusas indurescenti." Berzelius investigated the chemical properties of amber, and showed that it has considerable hardness and inflammability, and is strongly resistant to most agents as regards its solubility. He regarded it as an exudation from a plant, which, originally in the condi- tion of a balsam, afterwards hardened, haviug pre- viously entangled insects, &c, within its tenacious substance, t Although there is now no doubt as to the true nature of this resin, the exact age in which the parent trees flou- * 'Historic naturalis,' Pliny, Lib. xxxvii, xi. f The Latin succinum probably is from succtM juice. The Greek word i)\tKrpov is not so clear as to its signification. Perhaps the resin took its name from the golden alloy known by that name, the splendour of which, amber is thought to imitate. SOURCES OP AMBER. 161 rished is not certain. There seems, however, to be no hesitation in ascribing its age to the middle or later Tertiary times. The amber-bearing tree has been long extinct, but the causes which led to its disappearance can only be in- ferred. Probably they were chiefly of a climatal nature. The present principal sources for European amber occur on certain coast-beds of the Baltic Sea, and most noteworthy are those situated on the south and south- east parts which trend away from Memel towards Konigsberg, skirting the Gulf of Danzig, and the whole delta of the Vistula. The narrow necks of land which here jut into the sea also furnish numerous nodules of the resin. But although the sea-board offers great facilities to the amber-hunter on account of the eroding action of the waves, other localities occur inland ; and the gravel beds of various countries contain concretions in comparative abundance. Masses have been found in Prussia between Palmnicken and Habenicken, said to weigh thirteen, and even eighteen pounds. These specimens are to be seen in the Royal Cabinet at Berlin. The amber area, however, is very large, and comprises the shores of the Adriatic, Sicily, and Poland ; the clays of the Paris basin ; deposits near Gayhead in the United States of America ; Canada ; Cape Sable in Maryland ; Madagascar ; and it occurs also in Norway. In Great Britain amber is found in small quantities on the Nor- folk, Suffolk, and Essex coasts ; and Dr. Aikin found nodules also in the alluvial gravels near London. In a general way amber may be distinguished from copal and anime by its different density (specific gravity = P070 and hardness = 2*5), and its greater infu- sibility.* Of these resins, amber alone, perhaps, belongs to primaeval times. Copal, which most nearly * Aikin's 'Diet, of Chemistry,' i, 57; also Berzelius' 'Traite de Chemie,' vi, 589 ; Watts' ' Diet, of Chemistry.' Vide also Fothergill, " On the Origin of Amber," ' Phil. Trans.' for 1744 and 1745. VOL. IV. 11 162 BRITISH APHIDES. resembles amber, is, though perhaps not exclusively, the produce of the Mexican Rhus cop allina. Its sp. gr. is 1'39. Resin amine" is easily scratched, has a sp. gr. of 1'35, and is the produce of Ilymencea cowr- ba/ril. This last resin is exceedingly rich in enclosed insect remains ; but I have been unable as yet to dis- cover amongst the many specimens kindly lent for my inspection any trace of Aphides. As both these resins are of tropical origin, their absence need not cause any surprise. It is probably due to the fact that so many kinds of fruit, seed, and woody fragments have been embedded in amber, that such discordant views have been advanced as to its origin. The resin has been referred at different times to the oak, the poplar, and even to the palm-tree. From the peculiar character of the cellular tissue entangled in the masses, Prof. Goeppert refers the exudation to an extinct conifer, to which he gives the name Finns succinifer. This is now generally believed to be the true source of amber ; although, from the fact that other conifers are to be found associated with the amber masses, it is not certain that the excretions have but one single origin. There are several allied resins of different densities ; and probably they represent eras of different geological times. We have ambrite from New Zealand, walcho- wite, copalite, schlerotinite, and damar.* The examination of insects enclosed in resins of such high refractive power as amber and copal presents some difficulty. The rounded masses often act as lenses, and so scatter the light that the microscope can be rarely used until the specimens have undergone some mani- pulation. The most obvious and efficient mode is that of slitting and polishing the masses by aid of the lapi- dary's wheel. This is somewhat troublesome and costly, and has the disadvantage of injuring masses valued for ornament. * J. D. Dana, ' Manual of Mineralogy and Lithology,' 1879. APHIDES IN AMBER. 163 The Rev. F. W. Hope, many years ago, dissolved some of his specimens and successfully extricated the entombed insects ; but this must be a hazardous pro- cess, for amber is singularly indifferent to the action of most solvents.* Besides all this, insects in amber have been sufficiently prized to make attempts of their imitation remunerative, by slitting portions and again uniting them by a dense varnish after the surreptitious introduction of certain objects. When amber specimens are too valuable to cut up, much information may be gained optically by tempo- rarily cementing with Canada balsam small discs of thin microscopic glass, or even mica, over the specimens to be viewed. Sometimes a similar disc on the opposite side will be necessary ; care being taken to keep the sur- faces of both these discs parallel, otherwise the trans- mitted light will not come direct to the eye. The objective of the microscope will then penetrate far into the amber mass, and bring out details quite in- visible without such a treatment. At other times the whole specimen may be merged in a glass trough containing castor-oil, or some liquid of high refractive power, that does not act on the amber itself. After examination the specimen can be easily cleaned by using spirits of turpentine, which does not act on the amber. The earliest notices that I have met with as to Aphides in amber are by Dr. G. Carl Berendt, who, at various periods from 1830 up to the appearance of his great work in 1845, published papers on the fossil insects of the ancient world. f Amongst these earlier memoirs I find notices of seventeen specimens of Aphides of the genera comprising Aphis, Lachnus, and Schizoneura. Unfortunately, they are not figured, and it is not possible to compare other like specimens except by means of the identical ambers referred to. * F. W. Hope, " On Succinic Insects," ' Trans. Ent. Soc.,' Lond., iii, pp. 133 to 147. f G. 0. Berendt, ' Ein Beitrag zur Thiergeschichte der Vorwelt.' 164 BEITISH APHIDES. In the year 1856 Victor de Motschulsky communi- cated to M. Menetries, of Helsingfors, certain entomo- logical notes, amongst which he describes an apterous Aphis with long upturned cornicles. He says : — " Les Aphides se trouvent en tres grand nombre, surtout le Lachrms dryoides, Germari ; et parmi lesquels ils se trouve une espece que je nomme Apliioides smci/era, qui resemble en peu a notre Aphis pinophila, mais qui a les appendices de l'extremite de l'abdoinen tres long et diriges vers la tcte. II parait que c'est l'Aphis qui habitait l'arbre au succin, le Pinites succifer, Goep- pert."* I have reproduced the small figure of this apterous Aphis, which was embedded in a yellow amber mass ; " the produce of some tree analogous to our thuja " (Plate CXXXII, fig. 7). The same fine collection of ambers at Danzig, which contained upwards of 700 examples of various sizes, furnished four other examples of Aphides. Unfortu- nately no figures have been yet given of these speci- mens. They are catalogued by Prof. Menge amongst insects of ttie Eocene, and from beds referable to the Ligurian series. They are named respectively Ap h is la/rgiflua t A. retrolacteus, A. longicomis, and Lachnus glandulosus. Dr. George Carl Berendt issued the first volume of his fine work on the organic remains of the ancient world, as embedded in amber, in 1845. The second volume did not appear till 1856. Dr. Berendi died in 1850, and his collaborateur, 0. L. Koch, shortly before that period, viz. in 1849. The Orthoptera and Hemi- |i1ci;i woe described by Prof. Germar, but the editing of this second volume was by Dr. H. Hagen, and to this portion the reader is referred for many details not suited for this sketch of the amber Aphides. The succiniferous beds of the Baltic and Prussia are referable to the " Molasse." They overlie, or rather * ' Etude Ent.,' V, p. 29, fig. 8. Edited by V. de Motschulsky, 1856. f Mcnge, ' Progr. Petrischule,' Danzig, p. 19, 1859. APHIDES IN AMBER. 165 they date just after the era of the great salt formations of Grallicia and the North of Austria. A synopsis of these beds, as given by Berendt, is as follows : Fruit-bearing Shales. Alluvium. Younger diluvium. Northern gravel (Nordische Geschiebe). Younger sandstones. Beetle-clay in Cerithienkalk. Plastic clay. Brown coal (lignite) with Amber. Gallician salt formation. Limestone. I believe that a more detailed examination of the specimens themselves, with greater microscopic aid than has been hitherto used, will modify some of the genera ascribed by Berendt to these insects.* 2.— DIAGNOSIS OF APHIDES IN AMBER, AND DESCRIP- TION OF THE FIGURES IN PLATE CXXXI. Aphis akaneifoemis, Gerrnar and Berendt. Plate CXXXI, fig. 4, of this Monograph. Berendt' s description, very shortly giveu, is as follows : Antennse pilose and nearly the length of the body. 7-jointed. Legs not hairy. Rostrum not visible in this specimen. From the characteristic cornicles aud general appear- ance of the insect, I (the present author) would refer it to the genus Rhopalosiphum rather than to Aphis. In Berendt's description,* to which the reader is referred, the insect is thought to have some affinity with Aphis pomi of De Geer (A. mali of Schr.), but in * E. J. Germar u. G. C. Berendt, ' Die im Bernstein befindlichen Hemipteren u Orthopteren der Vorwelt.' Berlin, 1856. ' Organische Reste im Bernstein,' Band ii, Tab. i, figs. 4—8, and Tab. ii, fig. 1. 1 Aphidina,' pp. 4, 5 6, and 7; 1GG BRITISH APHIDES. the absence of living specimens for comparison, no safe conclusion can be come to as to identity. Vide vol. ii, p. 6, Germ, and Berendt. Aphis (?) hirsuta, Ger. and Ber. Plate CXXXI, fig. 5. Body lancet-shaped, studded with hooked bristles. Colour yellow or greenish. Darker beneath. This insect probably has more affinity with our recent Siphonophora rosarum, than with Aphis picridis s to which Berendt refers it. The amber must have been in a fluid state to have permitted the preservation of the minute hairs so distinctly seen in Berendt' s figure. See a full description, op. c, p. 6, Gerin. and Berendt. Laohnus (?) dryoides, Germ, and Ber. Plate CXXXI, figs. G and 7. Long oval, flatter above. Antennae less than half the length of the body. First joint short and thick, the second equally thick, but longer ; third somewhat shorter than the second and drawn out thinner ; the fourth smallest of all ; the fifth and sixth as long as the third ; and the seventh appearing as a nail-like pro- cess. The rostrum is very long, and projects about one third beyond the tail. It is 4-jointcd and shows an acute and narrow labrum. Berendt points out the resemblance this insect shows to " le Puceron du chene " of Reaumur, and to Lachnus queroHs of Burmeister. The general colour of the amber insect is yellowish-brown. Vide Germ, and Berendt. j op. c, vol. ii, p. 4. The articulation of the antenna is different from that in recent Lachninaa, and the rostrum also differs both as to length and articulate proportion. No necta- ries are marked in the anflber specimen ; though the APHIDES OF THE MIOCENE. 167 recent Lachninae show these organs clearly as papillae. The size of the insect is small as compared with the modern Stomaphis quercus ; but identity with this recent species is not to be expected at such a great in- terval of time, though affinities may be clearly traced. Laohnus (?) cimicoides, Germ, and Ber. Plate CXXXI fig. 8. This insect, as represented by the figure, is small and globular in shape. The details of the antennae are best obtained by a reference to the figure. It is diffi- cult to make any safe references here to any modern representative species, from the scanty materials at hand. The abdomen is slightly bristly ; and small tubercles are to be found near the spots from which they rise, and on the edges of the back. Vide Germ, and Ber., ojp. c, p. 5. Lachnus (?) longulus, Germ, and Ber. Plate CXXXI, fig. 9. Body three times as long as broad, its greatest width being at the post-thorax. Antennae hardly half the width of the body, 6-jointed, not counting the bristle-jointed apex. Cornicles wanting. Legs very short. Tail moderately long ; colour above, pale, with five long striped brown spots ; head and thorax brown, with the edges towards the joint brighter in colour. A comparison of the proportional joints of the antenna of this and the preceding Aphis will show that they cannot both belong to the same genus. "Without speaking positively on such small evidence as I possess, I would suggest an affinity with Brcbchy- colus stellarice, p. 147, vol ii, of this Monograph, and figured on Plate LXXXV, figs. 1—3. Vide Germ, and Ber., vol. ii, p. 5* 168 UKITISH APHIDES. Aphis (?) tkansparens, Germ, and Ber. Plate CXXXI, fig. 10. " Supra fusca, subtus pallida, pedibus fuscis, alis albis, nitidissimis, vena costali fusca." — Berendt. Perhaps a Laclmus ; but as the antennas are imper- fect and the wings cover the hinder part of the body, it is difficult to determine. The resemblance both in size and appearance to Aphis pmi perhaps justifies its reference to the genus Aphis. Berendt' s diagnosis in substance is as follows : — Head rounded in front, broader than the thorax, black above, pale below ; rostrum rather shorter than the body. Back (thorax ?) black, and divided into four lobes by a depression forming a St.-Andrew's cross. Abdomen short and broad. Lower parts of the sides seem to be raised into tubercles, but this may be due to the nodular form of the amber. Only one antenna is perfect. It is curved, with two small rounded basal joints, and a long clavate third joint, followed by two vasiform equal articula- lations, which together do not equal the third in length. The fourth joint is awl-shaped ; and perhaps a fifth and sixth joint once existed. Wings unusually large; round at the points, with a broad vein running parallel to the outer edge (cubitus), from which these oblique veins proceeded ; one of these has the usual furcation of Aphis. The hinder wings are small. The veins are not easily traceable. The colours appears to be pale, transparent, and shining. The legs are long, slender, and brown; tarsi 2- jointed, with two claws (perhaps intended by the term Zweilappig). As this is the only winged specimen figured by Berendt in the Prussian amber, I have given above his diagnosis pretty completely. Op. length of tin 1 whole body from head to apex as unity, to which all other measurements are referable. MIOCENE APHIDES OF AMERICA. 177 Antennae setaceous; length 1*7. Legs moderate, about equal in length to the antennas. Rostrum nor- mally long. Wings folded pent-wise; length =2. As this insect is seen in profile, the exact veining of the wings is not obvious. The whole insect recalls a recent Siphonophora rather than an Aphis proper. Reference to Siphonophora pelargonii. Mag. = 10 diam. Archilachnus pennatus, Buckton. Plate CXXXIII, fig. 3. Winged female. Body long and spindle-shaped; 1*0 X 0*4. Antennas about the length of the body, somewhat setaceous. Wings very long and narrow ; expanse 3 '3. Stigma also long and narrow. Cubital space partly filled with pigment. Stigmatic cell large. Cubitus twice forked. Insertions in the cubitus very far back in the wing. The two oblique veins spring very close to the insertion of the cubital vein. Hind wings wanting. No nectaries are visible. The abdomen seems to have been pale anqj. spotted. It appears to have been a fine species, perhaps allied to our recent Lachnus pinicolus. Mag. = 8 diam. Anconatus* dorsuosus, Buckton. Plate CXXXIII, fig. 4. Head, thorax, and abdomen very broad; 1*0 X 0*5. Two conical eminences seem to mark the seats of former cornicles. Wings with a strong cubitus and pointed stigma, which latter is carried partly round the stigmatic cell. Length of wing==l*5. The cubital vein has but a single fork. Oblique veins are two in number. * (From dyicwv, cubitus, an elbow). VOL. IV. 12 178 BRITISH APHIDES. This largo Aphis recalls, chiefly by the wing-vein- ing, a Schizoneura, but the form of the body better accords with a Lachnus. Mao-. — 6 diam. Schizonecroides Scuddeki, Buckton. Plate CXXXIII, fig. 5. Body long and oval. Eyes large. Thorax broadly banded with pigment. Abdomen distinctly ringed and barred with spots and fasciae very like a modern Aphis. Length to breadth as 1 to 0*3. Fore wing very broad, with a very indistinct stigma. Cubitus far removed from the costal margin. Stigmatic cell very large. Cubital vein ouce forked, and followed by two oblique veins, the second of which is much, curved. An under wing still remains with this specimen, but it is much folded. Neither antennas nor legs are to be seen in the matrix. The wing-veining is unusual, but possibly the insect may be referred for comparison to Schizoneura ulmi. Mag. = 12 diam. Pterostigma recurvum, Buckton. Plate CXXXIII, fig. 6. The body of this insect has some resemblance to the last insect, but it is too much crushed for a decision as to character. The abdomen is ornamented by six square patches of colour. The eyes are rather large. The antennas are fragmentary, but show two basal and the remains of two other joints. A ros- trum with three joints protrudes from one side of the bead. The wing is very long and pointed, with a remarkably attenuated stigma like that of Golopha ulmicola, Monell. If the stigmatic vein is not dis- placed by pressure, it is remarkable. Probably the cubital vein had one if not two furcations. Recalls Lachnus longistigma of Monell. Mag. = 8 diam. GEOGRAPHICAL DISTRIBUTION. 179 6.-DISTPJBUTION OF APHIDES. "We learn from their fossil remains that Aphides in ancient times were diffused over a large area of the world's surface. Their modern representatives are no less widely scattered. The fact also is interesting that so many well-known species are common to coun- tries widely separated by distance. Thus, out of the 185 British species and varieties in this Monograph, the annexed very imperfect table has been drawn up, which shows, subject to the uncertainty attendant on the strict identity of species at such distant parts, the diffusion of these insects over certain areas. Aphidinae. England. Germany. Italy. America. f Siphonophora < Aphis (. Other genera Lachninse Schizoneuringe Pemphiginae Chermesinaa Rhizobiinas 40 28 15 9 45 29 20 5 45 32 28 11 19 13 11 4 7 4 4 2 10 8 6 1 8 5 11 11 1 6 In answer to my inquiries, Mr. J. Monell, of St. Louis, writes that he thinks the most northern American Aphis yet described is Pemphigus tessellatus, Fitch. Hermaphis rhois also occurs far north in Ontario. Perhaps the most southern Aphis of North America is the cotton louse, Aphis gossipii, a published description of which is still wanting. It extends southwards to St. Louis, and eastwards throughout the whole length of the Mississippi valley. Pemphigus vagabundus is common over the greater part of the United States, and is found on the slopes of the mountains of Colorado. The Aphis-eating Asaphes is a native of South America ; and the Hemerobiinee and Coccinellidas are also widely spread over that continent. The presence 160 BRITISH APHIDES. of such insects, though strongly suggestive, is not conclusive as to the existence of Aphides in these districts. However, Aphides have been noted in Brazil by Lund, but I am ignorant of the species. This locality is the only one south of the equator where these insects are recorded as indigenous. Lachnus 'picece is one of the most northern insects known, and is indifferent to very low temperatures. It inhabits the forests of pine on the frozen tracts of Northern Asia, having been taken near Lake Baikal and the banks of the Amur. This insect also flourishes on the snow margins, and close to the glaciers of Switzerland. Dry obi us lives on the oaks of Croatia, as in Britain. Edward Doubleday,* assisted by Haliday, described an Asiatic Aphis which seems to have some connection with the genus Pemphigus, since, amongst other characters, it punctures a species of Rhus, and raises pseudo-galls, which are valued by the Chinese for the tannin they contain. A diagnosis is given by Doubleday, and also several figures ; but as the winged form is at present unknown, no certain genus can be assigned to the Aphis. This same gall, or one very dike it, has been also described by Walsh in America. Tropical heats are not well suited to the wants of an insect family so dependent as Aphides are on succulent food. Yet, as we approach climates made more temperate through the elevation above the sea-level, examples occur even but a few degrees above the equatorial zone. Through the kindness of Mr. Octavius Greig, two years ago, I received some insects from Kaladhungi, which is situated in the North-west Provinces of India. These proved to be Aphides. They were taken by him from rose trees in the garden of Sir Henry Ramsay in the month of October. These * E. Doubleday, " Am Aj.liis forming the Chinese Galls," 'Tram. Pbarm. Soc.,' vol. vii, No. 7, p. 310, U I INDIAN APHIDES. 181 insects, which were individuals out of companies of many hundreds, under the microscope showed all the characteristics of Siphonophora rosce, and, indeed, they were identical with our English rose Aphis. They were pretty constantly attended by ants, which coursed up and down the trees for the honeydew. The same gentleman also procured for me, in the following June, an Aphis which clustered on blades of grass growing on a wild flat in the neighbourhood of Bogsar in the same district. They belonged to the genus Aphis, and were exceedingly like the British Aphis jacobcecu. Ants also affected their company, specimens of which last insect he mounted for me in resin. Two or three winged forms were secured ; but, as they were unfortunately lost during their transit to England, I cannot give their diagnosis, though I possess the apterous females in resin. From Bogsar also I obtained specimens of a root- feeding Aphis possessing tarsi with a single claw and 5-jointed antenna?. They were infesting the roots of Zizyphus jujuba. No winged insects could be obtained though a search for them was made several times. I give the following description of this Indian Aphis : RHIZOBIUS .TUJUB2B, Bucktoil. Apterous viviparous female. Inch. Millimetres. Size of body 0'060 X 0-035 1-52 X 0*88. Length of antenna? 0'020 0*50. Cornicles wanting. Body oval, yellow, furnished with numerous stout bristles. Eyes very small; composed of a single lens, mounted on a conical process, which rises near the base of the antenna?. Antenna? short and 5-jointed, the apical joint being somewhat clavate. 182 BRITISH APHIDES. Legs short ; tarsi long, single-jointed, and furnished with a single claw and bristles. Rostrum short and extending to the second coxae. Habitat. — North-west Provinces of India. Thus the known area now covered by these interest- ing insects is a very large one, extending from Northern Siberia to the Brazils in the southern hemi- sphere ; from Colorado in the far west to New York ; from Britain to Croatia ; and from the Himalaya to China in the east. No notices yet have been published as to the occurrence of the family in Southern Africa, or in the temperate parts of Australia. Considerable interest will attach to any indigenous forms which may here- after be shown to exist in these parts of the world. 7.— OBSERVATIONS ON THE NATURAL AND ARTIFICIAL CHECKS TO THE INCREASE OF APHIDES. Although the primary aim of science is discovery, and the knowledge of laws which govern the universe, in a secondary manner we may well study phenomena in connection with our own economy, and their bear- ings on our material well-being and comfort. Some information may therefore be here expected, as to the methods, natural or artificial, which are of avail in controlling the spread of insect pests in general, and of Aphis in particular. As to the former subject, several notices will be found scattered throughout my previous volumes relating to the parasitic insects winch prey on Aphides ; and these parasites will be found the most powerful checks to Aphis increase, if perhaps we except all electrical storms, rains, and winds. As to the artificial methods, it must be confessed that, the numerous nostrums advocated ami published through various journals, both home and foreign, only prove how little we can do where CHECKS TO INCREASE OP APHIDES. 183 the evil is spread over a large area; the immediate destructive agents are legion, and their economy is often obscure. Some years ago Mr. F. Walker, after noticing the destruction of the water-lilies on the Thames near Hampton Court, suggested the artificial introduction, or transplanting, as it were, of diseased individuals of Rhopalosiphum nymphcece ; these Aphides being very commonly infested by the larvas of small Ichneumonida3 and Ohalcidise. These parasites would, after becoming winged, deposit their eggs in myriads of healthy Aphidian larvse, and thus check their evil influence. There can be no doubt that our corn harvest is repeatedly saved by the presence of the little black Ephedrus plagiator, which oviposits in the larvas of Siphonophora granaria. The brown, globular, ichneu- moned bodies of the rose Aphis is also familiar to most horticulturists. The common rape Aphis, Rhopa- losiphum dia?ithi,&nd the cabbage Aphis, Aphis brassicce, are so much attacked by parasites, that scarcely one individual in a hundred escapes and passes into the winged state. The hop-grower knows the value of the " lady-bird," and will not allow them to be wantonly destroyed ; and equal protection should be given to the Aphis-eating " golden-eye." Some Aphides undergo a sugary degeneration ; the internal organs apparently at first become abnormally charged with oily globules, which afterwards crystal- lise like grape sugar, and finally the insect is destroyed. The Aphides of the swede-turnip are often thus affected, and their bodies then turn to a foxy-yellow colour. Rhopalosiphum lactucce and many other species are often covered by a yellowish fur-like coat, which under the microscope has much the appearance of a fungus, not unlike the Empusa of the house-fly. The entire body of the insect becomes clothed with trans- parent ovoid bladders, interlaced with what appears to BRITISH APHIDES. be a connecting mycelium. On cutting into such bodies their contents will be found leather-like and tough, and finally the insects dry into hard masses. Dr. Worthington Smith states that the potatoe fungus, Peronospora infestans, passes its mycelium into the bodies of the Aphides, which commonly infest the stalks of that plant when diseased. That Aphides are liable to fungoid growths is clear from the observation of many investigators. In 1873 Dr. J. Le Conte, of Philadelphia, remarked on the epidemic diseases of insects ; and with a view to their extermination, he proposed something like the inoculation of disease. Dr. Rees and Mr. A. Giard subsequently discussed the same subject with the like intent. Very much to the same purpose Prof. Metschnikow suggested the deliberate cultivation of such fungoid growths as produce diseases in insects ; and he pro- posed that the fungi so cultivated should be scattered in places infested by noxious insects, with a view to their extermination. Dr. H. A. Hagen, of Cambridge, Mass., made experiments on the effects of common yeast on beetles, &c, and he states that sprinkling the bodies with this substance resulted in death of the insects within the space of three or four days. He thinks that destruction of the animal organs is caused by the penetration of the mycelium, which produces the consequent disintegration of the parts. It is not clear how this yeast-plant is most advan- tageously ;i|>|>lied ; but possibly a few insects, anointed with the scum from the brewing of beer, when set at liberty, would cause the required dissemination. I would commend such experiments to the notice of those who are overrun with the common cockroach. A little attention will always keep the " green-fly " out of greenhouses and forcing-pits. The great thing to avoid is insect possession through a neglect of the early broods of the year. These broods, being less INSECTICIDES. 185 numerous as to individuals, may be overlooked ; but they are the future centres of fresh companies. Pots plunged for a few moments into water heated to 140° Fahr. will kill most insects ; and probably in no case the treatment will injure the plants. Syringing with a weak solution of soft soap, that is, two ounces to the gallon of water, is efficacious. The potency of this wash is increased by boiling in it two ounces of flowers of sulphur. Sulphur, indeed, is the most important ingredient in the various washes offered to the public as insecticides. A cheap solution of calcium sulphide may be easily prepared by boiling together — Flowers of sulphur . . 1 lb. Caustic lime . . .2 lbs. Water ... .4 gallons. To prepare the liquid for use take of the above, Calcium sulphide . 4 ounces 1 -mt-. n c ,, r > Mix together, sort soap . . 2 ounces ) & Add hot water . 1 gallon. Stir and allow to settle. When cold, this liquid may be used as a bath, or sprinkled by the syringe or by the garden hand- engine, or by a brush ; this last instrument most effectively rubs the solution into buds and bark infested by Aphis. Some have strongly advocated a copious syringing of infected trees, when the thermometer is seven or more degrees below the freezing point. No injury is done to the trees by thus using the above solution ; " but the freezing and thawing loosens and clears the Aphis eggs out of innumerable crannies."* Smoke of all kinds has a sickening effect on Aphides ; and the old plan of fumigation by the slow combustion of coarse and wetted tobacco is very con- venient in glass houses and forcing-frames. MM. Monestier and Lauland recommend placing an * E. Ormerod, ' Manual,' p. 288. 186 BRITISH APHIDES. uncorked phial containing about two ounces of carbon disulphide close to the roots of such vines as are infected with Phylloxera vastatrix. The vapour is heavy, and it affects the soil and the insects below. The liquid must not be spilled ; and, as the vapour is poisonous, great caution obviously is needed in its use. During this last year (1882) M. Monillefert used the sulpho- carbonate of potassium on no less than three hundred and eighty-five vineyards, and he states he has met with great success. The cost varied from 0*05 to 0*03 of a franc per stock; which, considering the advantage gained, cannot be considered as an excessive cost to the grower. With reference to the hop Aphis, Phorodon humuli, there would seem to be but little doubt as to the hybernation either of the oviparous female or her ego;. An application of this sulpho-carbonate to the soil close to the root-stocks early in the spring, when the fundatrix is expected to hatch from the egg, surely is worthy of a trial. Its application to the hop plant cannot have greater difficulties than those experienced in the grape-vine. Both in France and America the substance known as Paris-green has been beneficially applied as an insecticide. But as the active principle is arseniate of copper, a highly poisonous preparation, and fatal to all animals, even in small doses, its use cannot be recom- mended. Careful washing of the hop plants soo7i after flir appearance of the hop Aphis has often insured a fine cropof blossoms to the grower, and notwithstanding the extra cost it will well repay him for his labour. This may be well understood, when one acre of ground may produce as much as seven hundredweights of hops, representing a value of £22. The loss over the United Kingdom caused by "the fly" during this last year is estimated by a large hop-grower at not less than £1,750,000, of which the labourers, through EXTERMINATION OP THE HOP APHIS. 187 deficiency of wages, &c, are thought to have sustained at least £200,000. The advice I here would give is to burn the vines immediately after the hops are picked ; watch for the foundress as she rises from the soil, and takes to the young plant when it is only a few inches high ; wash thoroughly, by hand at first ; and in February or March, on a sufficiently large scale ; and use the same means as our friends on the other side of the English Channel use to stamp out the Phylloxera. There is yet another consideration I here offer to those most interested in destroying Plwrodon humuli. As this species feeds on the green leaves, and has not been shown to be dependent on the root of Humulus lupulinus for its sustenance at any time, the life- cycle is complete in a single year. Therefore, if by mutual consent, no hops are grown (for say three years) on a district so wide that the winged insect is not likely to traverse it, a large portion of this area would be free from Aphis for an indefinite time. There can be no doubt that, as rapid locomotion and ready transit transplant fresh species of insects, into new localities, so isolation will be a chief factor in stamping them out. In connection with the economy of Plwrodon humuli, I will here state that, through the kindness of a friend living at Staplehurst in Kent, a block of earth, con- taining the root-stock of a hop plant which had been infected with fly during the previous year, was con- signed to me in March of this year. I spent nearly two hours in investigating the mass, taking a spoonful at a time, and viewing it under lenses of different magnifying powers. I could not find a trace of either Aphis or egg. The earth was rather pale in colour, so if a dozen eggs or even fewer had been present, I believe I should have seen them. A few small centi- pedes and the larva of a small beetle were the sole rewards of my pains. This earth from Staplehurst is now reserved for the 188 BRITISH APHIDES. purpose of securing any Aphis that may yet appear above ground. A similar negative result was obtained from the investigation of a quantity of half-dried leaves of tho hop gathered from the neighbourhood of the hop vines in late autumn.* I found many dead specimens of Aphis hinnuli which had been the prey of some small Ichneumon ; but I failed to find either male, female, or the winter egg, the true nidus of which is so much in request for deciding the agriculturist as to the best mode of meeting his insect foe. As investigators are likely to find the subterranean Tychea and Endeis in the soil of hop grounds, they must be prepared not to confound them with Phorodon, which has nectaries and the characteristic frontal tubercles. 8.— THE PRESERVATION AND MOUNTING OF APHIDES FOR THE MICROSCOPE. A few remarks embodying the author's experience as to the best mode of transmitting living Aphides from one country to another for the purpose of com- parison, and also the best method for killing and pre- serving such-like insects for future examination, may be acceptable. As to transmission, the chief thing to be guarded against is desiccation. Tenacity of life is so remark- able in these insects, that, almost like plants, they may be cut up and yet the dismembered portions will retain their irritability for hours, if they be only kept in a moist atmosphere. No plan appears to be so successful for the safe transit and security of the insects in a living * These leaves were kindly forwarded to ine by Miss E. Ormerod. The reader is referred to ber useful ' Manual of Injurious Inseets, and Rlethodfl of Prevention,' for much useful information therein con- tained. MOUNTING SPECIMENS. 189 state, as their enclosure in ordinary quills stopped by plugs of cork, or pellets of bees-wax. The sub- stance of the quill is sufficiently porous to prevent mildew on the one hand, and a rapid evaporation on the other. In this way small insects may be sent through the post, and in a far better condition than can be secured in any tin boxes, even though they be filled with leaves. If a slip of some succulent leaf be rolled round each quill, to retain moisture, a bundle will conveniently pass through the post ; and in such a manner I have received specimens from the north of Scotland and the south of France. Intimate domestic arrangements do not seem to be interfered with during such long journeys, for the family increase often con- tinues in full vigour. Aphides placed in boxes, instinc- tively run to the light, and they commonly escape through any accidental chink. In such boxes they have often arrived at the end of their journey, drowned in their own sweets and exudations. A still more vexatious accident may happen in such consignments. For want of due attention the larva of a Coccinella or Syrphus, perhaps, has been overlooked ; and the inter- loper has become fat on specimens set apart for other purposes. 9.— THE PRESERVATION OF APHIDES FOR THE MUSEUM. The presence of air with its floating germs is now admitted to be necessary for the fermentation and decomposition of both vegetable and animal sub- stances. It thus would appear that insects may be preserved for a time almost unlimited by sealing them from its influence in glass tubes. To those accustomed to the use of the blowpipe and lamp this operation will present no difficulty. Small, flattened, glass tubes, partially filled with a suitable liquid, into which the insects have been dropped, may ]90 BRITISH APHIDES. be drawn into a fine point. The end may be then broken off; and, by warming the empty space, or still better by expelling the air by a pump, a dozen or more tubes may, at the same time, be entirely filled with the liquid. The capillary tubes can then be sealed by the blow- pipe flame, and the specimens may be labelled in the ordinary way. As colours are liable to the bleaching action of light, the specimens are best ranged in a dark cabinet. Several liquids will be found effective, and they may be varied according to circumstances. I have had excellent results from very weak acetic acid, also weak glycerine. If alcohol be used, it must be exceedingly dilute, or it will render the insects opaque. But after all, for ordinary microscopic work, such as taking measurements, and noticing the constituents of the antennae and wings, nothing is better than care- ful mounting in Canada balsam, thinned, if necessary, with petroleum spirit. Just as insects are accidentally preserved in amber, they may be artificially and more completely secured, by embedding in any recent amber- like resin. If a few simple rules be followed, there is no difficulty in making these preparations ; and as to their showing detail, there seems to be nothing more to be desired. Although the procedure has been already lightly touched on in my first volume,* a recapitulation with additions may be useful. On a slip of ordinary-sized microscopic glass, dot from the head of a pin, in any desired order, five or a dozen spots of fluid Canada balsam, and by means of a hair pencil transfer as many living insects to them. The specimens at once adhere, and if the spots are small the insects spread out their limbs naturally, with a view to escape. They may be fixed on their backs or otherwise according to the views desired. A very thin glass cover or, if very high magnifying [towers arc wanted, a small disc of clear mica is laid * See Preface to Volume I. USE OF CANADA BALSA AM. 191 over the insects, and then one or more drops of the fluid balsam are delivered from a glass rod at one of the sides of these covers. The balsam runs slowly under by capillarity, and it drives all the air before it, the small weight of the cover assisting it to spread, until the whole area is filled. No pressure is to be used, or the elastic bodies of the Aphides will change shape ; and besides this, the juices will be forced through the cornicles and pores. If the balsam is thick, a very gentle heat, hardly exceeding that of the cheek, may be applied ; but, as a rule, the temperature of a room is better than that which exceeds it. The insects die immediately they are cut off from air, and in almost every case their position will be good for examination. To spread the wings of a small insect, the above- mentioned small dots may be made in a row. The belly of the specimen is applied to the middle spot, and by a bristle one wing may be applied to the dot on the one side and the other wing to the third dot. The cover is then placed as before, and when the balsam runs in, it will not disturb the position of the spread wings. It will be noticed that very soon after live insects have been mounted in a resinous substance that will not mix with water, a white cloudiness forms around each specimen. This is caused by the watery juices of the insect, which "chill" the medium and make it opaque. This cloudiness, however, entirely disappears after perhaps a month, the moisture being carried slowly outwards. The same is to be said of stray air-bubbles. The oxygen of the air unites with the balsam and thus hardens it ; but what combination is effected with the nitrogen is not so clear. However, air-bubbles in balsam disappear in time, provided the former is not in too hard a condition. In cases when the above small pressure is un- desirable, small circles, cut by round punches of different sizes out of very thin sheet lead, will be found 102 BBITISH APHIDES. more convenient to insert between the glass slip and its cover, than circles of card which are sometimes recommended. The thin sheet lead from the Chinese tea-chests is very suitable for punching, and as it is not porous like card, it yields no air-bubbles by heat. Herr D. von Schlechtendal has, in the ' Entomo- logische Nachrichten,' iv, p. 155, described a method, by which it would appear that all the characters of form and colour (?) may be preserved in Aphides and other insects. The method consists of a rapid death and drying of the insect by means of a current of heated air. The Aphis, previously attached to some suitable support, is suddenly and momentarily subjected to the heat of a spirit or other flame, by which it is imme- diately killed and caused to retain its natural position. Several examples are then carefully roasted in a current of hot air, such as that passing through an inclined glass tube, duly made hot, or dried on a sheet of paper moved over a heated metal plate. When dry, the specimens are mounted on card by attachment with gum-tragacanth ; or, as Mr. T. \\ r . Douglas suggests, more conveniently on mica, called 11 talc " in the shops, which, as it is incombustible, is well suited for a support both before and after drying. This method is vouched for as good by Drs. Giebel, Taschcnburg, Mayr, and Rudow. I have not tried this roasting process, but it must require some address to prevent the shrivelling of wings in such delicately formed insects, and to provide against the bursting action of the boiling juices. A more complete history of the process, than the foregoing, was given by Mr. T. Douglas in 1878.* M. Lichtenstein has many times been good enough to forward in Letters to me preparations of Aphides which have been secured between two films of mica. The insects, he explains, are immersed in a solution of resin in turpentine, "a natural amber," and, when all * ' Eut. Mouth. Mag.,' vol. xv, p. 164. DISSECTION OF APHIDES. 193 are in due position, the mica films are placed over apertures in card, and then gummed papers, similarly perforated, are pressed upon them. This arrange- ment secures all in their places. Methods and operations in science, like events in history, repeat themselves. Fifty years ago films of mica were used to cover objects for the microscope, and before the manufacture of the thin glass now so commonly used, it admirably answered its purpose. Under deep magnifying powers, such as -r^th of an inch, it will be found even now of great service. The mineral may be split by the lancet into films much thinner than glass can be blown in a flat state. Small unscratched pieces may be selected which are perfectly transparent and their cost is quite trifling. On account of the high refracting power of Canada balsam, the colours of recently immersed Aphides show themselves very brightly; and it sometimes happens that tints, quite lost through irradiation or glance on the surfaces, become distinct by treatment with this resin. The bright colours and markings of some species are due to the hue of the internal juices of the insects. These cannot be preserved by balsam, but it is other- wise with the pigments which stain the somewhat horny coverings of the thorax and abdomen. These colours are persistent. 10.— THE DISSECTION OF APHIDES In the dissection of Aphides, much assistance may be often got by a selection of liquids. Some of these are best suited for the purpose of hardening the tissues, so that they may bear separation and tearing asunder without their destruction. Others are used for colouring the transparent organs, so as to make them more visible. These organs of Aphides are so delicate that pure water will in a great measure destroy them, vol. iv. 13 101 BRITISH APHIDES. In such cases a weak solution of common salt, or very dilute glycerine, or sugar and water, or albumen and water, all of which should nearly approach the density of the juices of the insect, will be found a considerable help. Some Aphides are so large, so full of liquid, and so charged with oil-globules, that some treatment is necessary to reduce their bulk, and to allow of a sufficiently thin stratum of balsam for mountiug. In such cases the Aphides may be placed in spirits of turpentine, and just raised to the boiling-point in a small test-tube. After soaking in the turpentine for a few hours, all the oil-globules will be removed, and the insect, by this treatment, will have become very transparent, and the aqueous parts will not then chill the balsam. To prepare Aphides for dissection, liquids may be divided into those used for hardening the tissues and those employed for colouring the same. For harden- ing, a digestion for several hours in weak alcohol will be of advantage. The alcohol must not be too strong, or the albuminous portions will be coagulated and become too opaque. Weak acetic acid will render some portions tough, and the same action is also well effected by a weak solution of phosphoric or of nitric acid. The action of ordinary ether upon Aphides is not well understood. Their bodies are speedily destroyed by plunging them into the liquid. At the same time a considerable stream of air-bubbles contained in the tracheaa is expelled, and of such a volume as would lead to the supposition that much of this air must be in some state of solution in the body- juices. The reaction of weak potash has been before noted. As a rule, the germinal matter resists its action for a considerable time. Simultaneously this reagent usually stains it of a bright gamboge yellow. In some genera (notably Lachnus and Dryobius) potash deepens very markedly tho violet dyo natural to these Aphides. SALICINE IN APHIDES. 195 In other cases, I have found potash to evoke the violet shade from specimens otherwise colourless. This dye is fugitive, and, if discharged by an acid, cannot be again recovered by the action of an alkali. Soda and ammonia also bring out this colour. Advantage may be taken of the fact, that there is a certain order in which the tissues resist the intrusion of foreign matter, such as a dye. Thus the germinal and most vitally endowed organs reject dyeing by carmine, logwood, and such coal-colours as magenta ; whilst the portions in process of exfoliation and decay absorb it the most readily. For such purposes, weak alcohol may be made slightly alkaline by ammonia, and tinged with a little carmine or cocchineal solution. Dilute chromic acid both tinges the tissues yellow and renders them tough. Solutions of osmic acid also may be used with advantage, and, in short, the usual reagents employed for conducting minute anatomy may be taken with due circumspection and tenderness. For labelling specimens, paste will be found much more adherent than gum. The former may be pre- served for some months in a well-closed bottle, if a little aqueous solution of corrosive sublimate be stirred into it. 11.— SALICINE IN APHIDES. Mr. C. T. Muller, of Eastbourne, informs me that he has been able to prove the presence of salicine in the juices of Lachnus viminalis. He digests the insects in chloroform, which liquid subsequently, on evaporation, leaves silky crystals, capable of polarising light, and giving the characteristic red coloration with sulphuric acid. If these crystals be salicine, the polarised ray should have a rotation to the left. This experiment I have 196 BRITISH APHIDES. not tried. I am told that these crystals answer to the ordinary tests for salicine. The elaboration, or even the concentration of vege- table alkaloids in the organs of insects is very interest- ing. Chrysomela populi is known to leave a track of salicylic acid behind it when irritated. The botanical genera of Salix and Popnlus contain this bitter principle in their barks, and they are the chief sources for its commercial preparation, valuable as a febrifuge. APPENDIX. Our modern facilities for transport are now so great, that it becomes necessary to modify our notions as to when an animal is entitled to the term indigenous ; indeed, the naturalisation of a species now becomes merely a question of the period of time, and the degree of persistence. Perhaps only two Aphides out of the series I have described have been introductions into Britain within historic times. They are the American apple Schizo- neura and the grape Phylloxera. In the March of this present year I received from Mr. J. Anderson, of Chichester, an interesting addition to our list of Aphides. As they apparently infest only the palms, orchids, and a few other stove-plants, they must be looked upon as a species introduced from without. An examination of these insects proves them to be identical with a species described some years ago by M. Boisduval, in his * Entomologie Agricole,' to which he gave the name of Coccus latanice ; but M. Lichten- stein has recently shown that it agrees with that family neither in the construction of their antennas, nor in the characters of their tarsi. Besides this, M. Lichtenstein has satisfied himself that the rare winged form of this insect is a true Aphis; allied, perhaps, to Schizoneura, or to some near genus. M. Signoret had previously shown that it differed from Coccus, and accordingly he changed the name to Boisdiivalia latanice. M. Lichtenstein published at Montpelier a more complete diagnosis, and at the same time described the rare winged female. From the presence of two minute horns on the vertex of the 198 BRITISH APHIDES. apterous female, he gave it the generic name of Cerataphis. Mr. J. Anderson this year has made this addition to our list of British Aphides ; and thus he enables me to give a diagnosis of the insect as it appears in Great Britain. Unfortunately, the notice of its occurrence was forwarded to me too late to allow of its introduc- tion into the body of this work. G-enus XXV, bis. — Cerataphis,* Llcht. Rostrum of the imago short. Antennas 5-jointed ; the first two joints smooth, all the rest ringed. The third joint the longest, the fourth and fifth nearly equal. Eyes large. Nectaries none. Tarsi with two claws. Eyes of the larva nearly obsolete. Head furnished with two minute, characteristic, frontal horns. Legs and antennas very short, and mostly concealed by a disc of wax-like material, which is expelled from a row of peripheral glands. Cerataphis latanue, Lieht. Plate CXXXIY. Coccus latanice, Boisduval. i tfW Boisduvalia latanice, Signoret. I ^ /0 Cerataphis latamm^ Lichtenstein. Apterous female. Inch. Millimetres. Size of body 0-060 X 0*050 1'52 X 127 Antenna 0-010 0'25 Coccus-like. Colour rich brown ; to the naked eye, nearly black. Form oval, or nearly circular. Edge * From Ktjjae, a hora. APPENDIX. 199 of the body terminated by a string of minnte trans- parent glands, from which a clear disc of wax-like substance is secreted. This disc is striated and slightly fimbriated. It entirely surrounds the insect, and hides the antennas and legs below. In the Spring of the year, two or three pale folds occur across the dorsum of the insect. Antennas very short ; 4-jointed, the first and second joints nearly equal ; the third the longest, and about double the length of the second. The fourth joint ends in a considerable nail, which, added to the rest, makes the whole joint nearly as long as the third. The front is furnished with two short projections or horns, the use of which is unknown. Eyes very minute ; brown. Legs very short, and normally formed like Aphis ; ending with the usual tarsus and two claws, without the capitate hairs to be seen in coccus. Rostrum about one fourth the length of the body. Cauda tuberculate, with two small papillae. The underside is paler, and mottled with brown. The young, born from the above insects, are much less coccus-like, and do not greatly resemble their parents. After a short time they moult, and become of a pale, ochreous green colour. The wax glands soon after show themselves at the circumference of their bodies, and the growth of the disc is rapid and very interesting under the microscope. Viviparous winged female. Inch. Millimetres. Expanse of wings 0'160 4*06 Size of the body 0-0700X 0-040 177xl'01. Antennas O035 0*88. The imago apparently is very rare, for only three mutilated specimens are at present known. It has not yet been taken in England ; but I have been able 2(J0 BRITISH APSIDES. to make the above measurements from a specimen mounted by M. Richter, of Montpelier. General colour, yellow. Antenna3 with five articu- lations : the last three joints are much ringed. Vertex fiat, and without the horns seen in the larva. Eyes large ; stemmata obvious. Wings folded flat on the back. Cubital vein is once forked; and it does not reach to the cubitus. First and second oblique veins unite just before they touch the cubitus. Rostrum reaches to the second coxae. Legs short, tarsi with two claws. The general appearance of the larva is so coccus- like, that the venation shown by the imago is a little unexpected. Although this Aphis takes its specific name from the palm-tree, it really affects many other plants in the hot-houses of the horticulturist. M. Lichtenstein says that the larva is very abundant on Latania, Calamus, &c. It occurs here on Orchis and other plants. To the naked eye, they appear as black spots surrounded with white rings. They make patches on the leaves composed of twenty or more individuals. "When once the Aphis attaches itself, it does not appear again to move from its place, but the young rove about for some time after their birth. M. Lichtenstein thinks that the imago has some resemblance to Vacuna (Thelaxes), but it certainly wants the characteristic cornicles. I am unable to state the venation of the lower wings. I counted at least eight embryos within the abdominal cavity of the imago; so the imperfect sexes of this species arc clearly viviparous. The generic name of this insect must not be con- founded with Cerasaphis, of Amyot, which feeds on the cherry tree. 201 CONCLUSION. In taking a retrospective glance over the subjects treated of in these volumes, the author expresses his adherence to and entire belief in the old, but now often assailed doctrine of design. Mr. Darwin never taught that any blind condition was involved in selection, though some modern writers have illogically asserted that gradual evolution is utterly fatal to the argument of teleology. It seems to be inconsistent that these thinkers commonly use, and apparently from necessity, such a phraseology as in- volves a doctrine, the significance of which they would otherwise deny. It is the duty of the man of science to push back the sequence of cause and effect to the utmost attain- able limits; but this process, whilst it enlarges the area of the known, at the same time surely expands the horizon, which at present cuts us off from the vast region of the unseen ; for knowledge, like time, space, and number, is to us only relative. It is difficult to understand the position of that mind, which, whilst continuously acknowledging the sequence of cause and effect through a thousand instances, at the last stage of thought seeks, and apparently finds, some sort of relief in an inversion of this process, that is to say, by putting the effect first. A denial of the Causa causarum invites back that chaos and despair which would land intellect in the monstrous dogma, that this universe after all is but a mistake, and to man a hideous enigma, instead of being the visible exponent of the Infinite. Carlyle thus 202 BRITISH APHIDES. speaks of tlie kosinos — " The universe is not dead, and demoniacal ; a charnel Louse with spectres ; but God-like, and my Father's." And yet again, a student of old has nobly written to the same purpose. Bacon says, " Knowledge is not a couch whereon to rest a searching and restless spirit; nor a terrace for a wandering and variable mind to walk up and down with a fair prospect ; nor a tower of state for a proud mind to raise itself upon ; nor a fort or commanding ground for strife and contention ; nor a shop for profit or sale ; but a rich store-house, for the glory of the Creator, and the relief of man's estate." BIBLIOGRAPHY OF AUTHORS WHO HAVE TREATED OF THE LIFE-HISTORY OR OF THE ANATOMY OF APHIDES. i^ Amyot, 0. J. B. et Serville, A. Hist. Nat. des In- sectes. (Suites a Buffon). Hemipteres, pp. 597 —609. 1843. Audoutn, J. Y. Observations sur alteration qui pro- duit Puceron lanigere. Ann. Soc. Ent. France, t. iv, Bull. p. ix. 1833. Balbiani, E. G. Sur la reproduction et l'embryogenie des Pucerons, Comp. Rend., t. Ixii, pp. 1231, 1285, 1390. 1866. Mem. sur la generation des Aphides, Ann. de Sci. Nat., ser. 5, t. xi, p. 5, 1869 ; xiv, art. 2 et 9, 1870 ; xv, art. 1 et 4, 1872. Ditto, Bibliotheque des Hautes Etudes. 1870. Sur le Phylloxera aile, Comp. Rend., t. lxxix, p. 562. 1874. Sur la Phylloxera vas- tatrix, Comp. Rend., t. lxxix, pp. 685, 991, 1371. 1874. Balbiani and Signoret. Puceron de Terable, Comp. Rend., t. lxiv, p. 1259. 1867. Baleour, F. M. Treatise on Comparative Embryo- logy, vol. i, pp. 11, 61, 95, 345, 355. 1880. Berendt, G. C. Organischen Reste im Bernstein, bd. ii, pp. 4—7. 1856. Blot, F. Mem. Soc. Lin. du Calvados, Caen, t. i, p. 114. 1824. Boisduval. Monographie des Aleurodes. 1867. 204 BRITISH APftlDES. Boisier de Sauvages. Sur l'origiiie du miel ; Journ. do Physique, t. i, pp. 195, 196. 1773. Bonnet, C. (Euvres d'bist. Natur. (Observations sur les Pucerous), t. i, pp. 1—113. 1779. Boussingault. Matiere sucree sur les feuilles d'uu tilleul. Comp. Rend., t. lxxiv, p. 87. 1872. Boyer de Fonscolomee. Notice sur Phylloxera, Ann. Soc. Ent. France, t. iii, p. 219. 1834. Descrip- tion des Pucerons aux environs d'Aix, Ann. Soc. Ent. de France, t. x, p. 157. 1811. Brandt, Alex. Ueber das Ei unci seine Bildungsstittte. 1878. Also Beitrage z. Entwickelungsgeschichte d. Libelluliden u. Hemipteren. Mem. Acad. Petersb., t. xiii, No. 1. 1869. Brodie, P. B. Fossil Insects in Secondary Bocks of England. 1845. Bukmeister. Handb. der Ent., transl. by W. E. Shuckard. 1836. Carpenter, W. B. Principles of Comparative Physi- ology, pp. 385, 958. 1851. Clapaeede, E. Sur la reproduction des Pucerons, Ann. des Sc. Nat., ser. 5, t. vii, p. 21. 1867. Cornu, M. Le Plrylloxera ; Rapports pub. par le Ministre de l'Agriculturo, p. 9. 1879. Vide Nature, vol. xxiii, p. 127 (December, 1880), 1881. Courciiet, L. Etudes sur les Galles, Montpcllier. 1879. Curtis, J. Fossil Insects found near Aix in Provence, Edin. New Phil. Journ., vol. vii, p. 293. 1829. Farm Insects, Agric. Soc. Journ., iii, p. 49. 1842. Curtis, W. Aphides, Cause of Blight, Linn. Trans., vol. vi, p. 75. 1802. Deeijes. Ann. des Sci. Nat., t. xi, p. 93. 1869. Dui'OUR, L£on. Sur Coccus zea3 maidis, Ann. des Sc. Nat., t. ii, p. 204. 1824. Recherches Auato- juiques sur les Orthoptt-res, Zeitschr. f. Wiss. Zool., t. vii. 1841. Kechcrches Anatomiques sur les Hc^mipteres (Aphidiens), Mum. Acad. France, t, iv,pp. 241, 359, 387. L833. BIBLIOGRAPHY. 205 Dutrochet, H. Observations sur les Organs de la Generation chez les Pncerons, Ann. des Sci., t. xxx, p. 204. 1833. Duvatj, Aug. Nouv. rech. sur l'hist. nat. des Puce- rons, Mem. mus. d'hist. nat., t. xiii, p. 126. 1825. ^ Fabricius, I. C. Systema Rhyngotorum, pp. 294 — 302. 1822. Fitch, Asa. 1st and 2nd Report on noxious and beneficial Insects of State of New York, pp. 5 — 11, 49—102, 122—138, 155—159, 163—166, 318 320. 1856. 5th Report. 1859. Fonscolombe, Boyer de. See Boyer de Fonscolombe. Fothergtll, J. Essay upon Origin of Amber, Phil. Trans., vol. xliii, p. 21. 1746. ^Trisch, J. L. Beschreibung Insecten, b. ii, 1721; b. xi, 1734. Gardeners' Chronicle. Numerous papers on Aphides, for list, see p. 191, vol. for 1858. (^GrEER, C. de. Histoire des Insectes, t. iii, pp. 19 — 129. 1773. G-eoffroy, E. L. Hist, des Insectes, t. i, pp. 489 — 498. 1764. Germar, E. and F. Vide Berendt on Amber. Gerstaecker, O. E. A. Die Klassen u. Ordnungen der Arthropoden. 1866. G-irard, M. Le Phylloxera de la vigne. 1874. Rap- port de 1' Agriculture. 1879. Gleichen, F. F. W. von. Gesch. der Blattlause. 1770. y Gmelin. Lin. Syst. Nat., t. i, pars iii, p. 2201. 1788. Goedart, J. De Insectis. 1685. Goeppert, H. R., u Berendt. Der Bernstein. 1845. Goeze, J. A. E. Ent. Beitrage, b. ii, p. 286. 1778. Goss, H. Geological Antiquity of Insects. 1880. Haeckel, Ernst. Anthropogenic 1879. Hagen, H. A. Das Bernsteinland. 1850. Haliday, A. H. On New British Insects, Ann. Nat. Hist., vol. ii, p. 189. 1839. 206 BRITISH APHIDES. Harris, T. TV. Insects of New England injurious to vegetation. 1842. Ys Hartig, T. Eintheil der Pflanzenlaus, Gerniar. Zeit., b. iii, p. 358. 1841. Hausmanx, J. F. G-eschichte der Blattliiuse. Illigers Mag., t, i, p. u 229. 1802. Heer, Oswald. Primeval World of Switzerland, vol. ii, p. 47. 187G. Die Insecten-fauna der Tertiarge- bilde von Oeningen u. von Rabodoj. Theil iii, p. 121, 1853. Heyden, 0. von. Fortpfl. Gesch. Blattlause, Stett. Ent. Zeit., p. 83. 1857. Mus. Senckenberg, b. ii, p. 296. 1837. Huber, Pierre. On Ants, transl. by Jolinson. 1820. Huxley, Thos. Agamic Reproduction and Morphology of Apliis, Linn. Trans., vol. xxii, pp. 193, 221. 1859. Kaltexbach, J. H. Monograph d. Pflanzenlause. 1843. Fiinf neue Sp. Pflanzenlause, Stett. Ent. Zeit., b. vii, p. 169. 1846. Kessler, H. F. Lebensgeschichte der auf Ulmus Aphiden-Arten. 1878. Kirby and Spence. Introduct. to Entomology, vols. i, ii. 1815. Koch, C. L. Die Pflanzenlause. 1854. Kyber. Einige Erfahrungen iiber Blattlause, Germar. Mag. Entom., b. i, p. 1. 1815. Latreille, P. A. Considerations generates, Crust, et Insect,, p. 265. 1810. LEAcn, yV. E. Tabular View of Characters of four classes (Insects), Trans. Linn. Soc, vol. xi, p. 306. 1815. Leuckart, R. Die Fortpflanzung der Rindenliiuse, Arch. f. Naturgcsch., b. xxv, p. 209. 1859. Leeuwexhoek, A. van. Arcana Natura?, t. i, p. 548. 1695. v Leydig, F. Einige Bemerkungcn fiber Entwickluiig der Blattliiuse, Zeitsch. f. IViss. Zool., b.ii, p. 62. 1850. BIBLIOGRAPHY. 207 Lichtenstein, J. Hist, du Gen. Phylloxera. 1876. Notes pour servir a Phistoire des Insectes du genre Phylloxera, Ann. Agronomiques, No. 1, t. ii, p. 127. 1876. No. 2, t. iii, p. 35. 1877. Geschicte der Gattung Phylloxera, Stettin Entom. Zeitung, p. 71. 1877. Notes sur les Phylloxeriens, Ann. Soc. Ent. Belgique, t. xix, p. 164. 1876. Considera- tions sur la Generation des Puceron, Comp. Rend. Soc. Ent. Beige, t. xxi, p. ccxlv. 1878. Sur la Gemmation chez les Insectes, Oomp. Rend. Soc. Ent. Beige, p. lxii. 1878. LiNNiEus. Syst. Naturae, t. i, pars ii, p. 733. 1767. Fauna Suecica, pp. 216—218. 1746. \s Low, Franz. Ueber eine dem Mais schadliche Aphiden- art, Abhand. Zool. Bot. Ges. Wien., b. xxvii, p. 799. 1877. Lubbock, J. Ova and Pseudova of Insects, Phil. Trans., vol. cxlix. 1860. Collembola and Thy- sanura, Ray Soc. 1873. Ants and Bees, Journ. Linn. Soc, vol. xiv, p. 607. 1879. Yol. xv, p. 167. 1881 . Menge, A. Lebenszeichen im Bernstein. 1859. ^Mecznikow, E. Embryologie der Hemipteren. Zool., b. xvi, p. 128. 1866. Erubry. Stud. Insecten, ibid., p. 389. Zeit. f. Wiss. 1866. Moreen, Ch. Puceron du Pecher, Ann. Sc. Nat., 2 ser.,t. vi,p. 65. 1836. ^ Monell, J. Vide Riley Ch. Moseley, 0. On Aphis lanigera, Hort. Soc. Trans., iii, p. 54. 1820. Motschulsey,V. Etudes Entom., 5e annee, p. 29. 1856. Muller, C. J. Colouring Matter of Willow Tree Aphis, Jour. Roy. Mic. Soc, ser. 2, vol. ii, p. 39. 1882. Newport, G. Development of Myriapoda, Phil. Trans., part i, p. 99, for the year 1841. Genera- tion of Aphides, Linn. Trans., vol. xx, p. 281. 1851. Ormerod, Miss E. Notes of Observations of injurious v,-~> vy 208 BRITISH APHIDES. Insects, Report for 1879, pp. 40, 41. 1880. Ibid., Report for 1880, pp. 24, 29, 30, 32. 1881. Ibid., Report for 1881, pp. 1, 14. 1882. Manual of injurious Insects, pp. 4, 20, 63, 97, 119, 143, 192, 240, 247, 254, 272, 293. 1881. Owen, R. Lectures on the Comparative Anatomy of Invertebrate Animals, p. 225, ct seq. 1843. Lecture, Royal Institution Proa, vol. i, p. 9. 185 I . Packard, A. S. Synthetic Types of Insects, Journ. Nat. Hist, of Boston, vol. vii, p. 591. 1863. Guide to the Study of Insects. 1880. Passerini, G-. Gli Afidi. 1860. Aphididse Italicse. 1863. Flora degli Afidi Italiani, 1863. Percival, C. H. (Her Majesty's Consul at Bordeaux). Report as to the Protection of Vines from the Phylloxera. 1881. Planchon, J. E. La defense contre le phylloxera, Ann. Agrom., t. i, p. 74. 1875. Ratzebukg, J. C. Forst.-Insecten, oder Abbildung und Beschreibung &c, b. iii. 1844. R^admur, R. A. Mem. pour servir a l'histoire des Insectes, t. iii, Mem. ix, p. 281. 1737. Riley, Chas. Report on noxious Insects of Missouri, pp. 84 — 96, 1871. Les especes Americaines du genre Phylloxera, Comp. Rend., t. lxxix, p. 1384. 1874. Riley, C, and Monell, J. On Aphididas of U.S. of America, Bull. Geol. Survey, vol. v, p. 1. 1879. Rondani, N. Osserv. Afid, Ann. delle Scienze Nat. de Bologna, 2 ser., t. viii,pp. 337 et 432. 1847. Rossi, P. Fauna Etrusca., t. ii, p. 406, No. 1396. 1807. "Rusticus." Observ. on Blight, pp. 33, 143, 217, 363, 425, Ent. Mag., vol. i. 1833. Samouelle, Gh Entomologist's Compendium, p. 232. 1819. ScinoDTE, J. C. Rhynchota, Naturhist. Tidsskrift, ser. 3, vol. vi, Trans!., Ann. Mag. Nat* Hist., vol. vi, 4 ser., p. 225. 1870. BIBLIOGRAPHY. 209 Sohlechtendal, D. von. Verschrumpfeii Insecten fur Sammlungen. Entomologisclie Nachrichten, b. iv, p. 155. 1878. Schmidberger, J. Beitriige zar Obstbaumen sclnid- liclien Insecten. 1836. Schrank, F. Fauna Boica, vol. ii. 1801. Scopoli, J. A. Entomologia Carniolica, p. 136. 1763. Scudder, S. H. Terfc. Lake Basin at Florissant, Geol. Survey of the Territories, U.S., vol. vi, p. 279. 1881. Early Types of Insects, Mem. Boston Soc. Nat. Hist., vol. hi, p. 13. 1879. Shaw, G. Gen. Zoology., vol. vi, p. 168. 1806. Siebold, 0. Th. von. IJeber die inneren Geschlechts- , werkzeuge der viviparen u. oviparen Blattlause ; Froriep's Neue Notizen, b. xh, p. 305. 1839. Signoret. Etudes sur le genre Phylloxera, Ann. Soc. Ent. de France, t. vii, p. 297. 1867. On Phyl- loxera vastatrix, t. ix, p. 549. 1869. Vide Bal- biani. Smee, A. My Garden, p. 477. 1872. Sorby, H. 0. On Colouring Matter of Aphides, Quart. Journ. Mic. Science, vol. xi, New Series, p. 352. 1871. Sulzer, I. H. Kennzeichen Insekten, p. 105. 1761. Swammerdam, I. Hist. Insect. 1693. Targioni Tozzetti. Bull. Ent. Ital., p. 236, ix. 1877. Thomas, Cyrus. Eighth Report on noxious and beneficial Insects of Illinois. 1879. Thomson, Allen. " Ovum," Todd's Cycl. of Anatomy and Physiology, vol. v, p. 1. 1859. t Turton, W. Transl. Linne, Sys. Nat., vol. ii, p. 702. 1802. "Walker, Francis. Descriptions of Aphides, Ann. Nat. Hist., ser. 2, vol. i, pp. 249, 328, 443, 1848 ; vol. ii, pp. 43, 95, 190, 421, 1848 ; vol. hi, pp. 43, 295, 1849; vol. iv, pp. 41, 195, .1849; vol. v, pp. 14, 269, 388, 1850 ; vol. vi, pp. 41, 118, 1850. Remarks on Migrations of Aphides, Ann. Nat. vol. iv. 14 210 BRITISH APniDES. Hist, ser. 2, vol. i, p. 372. 1848. Aphides and their Food Plants, Zoologist, vol. iv, p. 1288. 1846. See also Zoologist, vol. iv, pp. 1359, 1461 ; vol. vi, pp. 2217, 2246, 1848; vol. vii, pp. xxxi, xliii, 1849 ; p. cii, 1850. Catalogue of Homop- tera, British Museum, part iv, 1852 ; and Supple- ment. 1858. Westwood, J. 0. Introduction to Modern Class, of Insects, Aphidoe, vol. ii, p. 437. 1840. Habits of Insect Parasitic on Eose Louse, Mag. Nat. Hist., vol. vi, p. 491. 1833. Introductory Observations on Fossil Insects in Brodie's Fossil Insects. 1845. Witlaczil, F. Zur Anatomie der Aphiden, Arbeit. Zool. Instit, Wien, b. iv, p. 397. 1882. Also Abstract, Journ. B. Micro. Soc, ser. 2, vol. iii, pt. 1, pp. 49 —51. 1883. Zetteestedt, J. W. Insecta Lapponica, vol. i, p. 306. 1840. The above is not an exhaustive list of the writers on Aphides, but it is believed that all the chief known facts, as connected with their economy, can be extracted from the memoirs above named. GENERAL INDEX TO VOLS. I, II, III, AND IV. Abdomen, number of segments of Addenda Adelges abietis — gallarum abietis Adipose secretions Alkalies, action of, in evoking dye tints Allen Thompson on ovum of Aphis Amber, antiquity of Aphides inclosed in — Baltic-beds of — best modes of viewing insects in — Bei-endt and Germar on . — Motschulsky on . — Menge on — resins allied to . American blight, first appearance of, in England Amphorophora ampullata Amycla fuscifrons — fuscicornis Anatomy, alimentary system — circulatory system — hepatic vessels — respiratory system — salivary glands Analysis of honey dew . Anconatus dorsuosus Andrew Knight on self-fertilization Anisophleba pini Anocecia comi ' . Antenna, variable as to the number of joints Antiquity of the Hemiptera Ants and aphides, relations between — nests tenanted by Aphides . Aphides in the Eocene . — in the Miocene . PAGE . i, 19 ii, 176 ; iv, 104 iv, 24 iv, 24 i, 47 iv, 194 i, 66 iv, 160 iv, 161 iv, 163 163, 165 iv, 164 iv, 164 iv, 162 iii, 91 i, 187 115, 126 iii, 124 i, 32 i, 35 33 34 33 42 iv, 177 i, 68 iv, 40 iii, 107 i, 12 iv, 144 iv, 95 iii, 69 iv, 152 iv, 153 iii, 113, l, i, 212 GENERAL INDEX. Aphides in the Tertiary beds of N. America — in the Wealden AphididsB found with Cicadida: in the Purbeck beds AphidinsB, synopsis of Aphidius gregarius — rosie, attack of Aphidivorous insects, Chalcidia3 — Coccimellid — Crabronidas — Cynipida3 — Hyruenopter — Ichneuuumida) Aphioides bursaria — succifera, fossil Aphis, artificial grouping of — synopsis of — tenacity of life in — abictina — aceris — acetoato . — alni — amygdali — auteiinata — aquilegisa — araneiformis, fossil — artemisiaj — arundinis — atriplicis — aucuparia; — bellis — berberidis — betulae . — betulicola — brassicas — bursaria — calamaphis — campanula) — capreas — capsella) — cardui — carduina — carotaj . — cerasifolia? — chenopodii — chloris — chrysauthenii — cieuta) — coryli — orategaria — crategi — cueui biti — dahlia — diantbi — vit-'iitul.'. PAGE iv, 156, 173 iv, 148 iii, 3 iv, 8 ii, 23 ii, 152 ii, 153 i, 170 ii, 158 ii, 150 ii, 149 ii, 151 iii, 117 iv, 164 ii, 31 ii, 30 ii, 48 ii, 43 ii, 121 ii, 80 iii, 31 ii, 99, 104 iii, 14 ii, 114 iv, 165 ii, 146 111,112 ii, 87 ii, 76 ii, 98 ii, 14 iii, 14 iii, 15 ii, 33 iii, 117 ii, 111 i, 161 ii, 27, 136 i, 121 ii, 92 i, 164 ii, 38 i, 176 87 55 92 27 17 37 35 56 82 15 39 ii, ii, ii. ii, iii, ii, ii, i', i', ii, ii, GENERAL INDEX. 213 Aphis epilobii — eriophori — euonynri — euphorbias — fabse — fagi — farfarse — floris rapse — foliorum — gallarum — gallarum ulmi — genistas — genistifex — granulatus — hederaa — hieracii — hirsuta — instabilis — insititia, Koch. — jacobsese — juglandicola — juglandis — laburni — lactucas — lanigera — largiflua, fossil — lata — lathyri, Walk — lentiginis — lencanthemi — ligustri — longicaudatus ; see descript: — longicornis, fossil — longipes — longirostris — lychnidis — macrostyla — mali — malvse — molluginis — morlotti, fossil — niyosotidis — nnda pini — nymphseas — cegopodii — onobrychis, Fonsc. — opima — oxycanthae — padi — papaveris — pastinaceae — pedicularis — penicillata — perforates ion of Fig. 1, Plate CXXXII PAGE ii, 71 ii, 117 ii, 72 ii, 82 ii, 81 . iii, 37 . ii, G8 • ii, 33 . iii, 97 . ii, 146 . iii, 131 . ii, 81 ii, 82 . ii, HO ii, 75 • ."' 67 • ivj 166 ii, 94 i, 178 ■ ", 79 . iii, 32 . iii, 40 . ii, 86 . ii, 10 . iii, 89 . iv, 164 ii, 93 i, 134 . ii, 59 • ii, 92 • ii, 13 I iv, • iv, 164 • !!!> 59 . iii, 62 • ii, 73 . iv, 169 . ii, 44 . ii, 42 . ii, 80 . iv, 171 . ii, 102 • *H» 50 ii, 12 ii, 27 i, 134 ii, 101 ii, 37 ii, 61 ii, 91 ii, 24 • H' 41 ii, 51 • », 132 L>1 L GENERAL INDEX. Apbis persicoe — porsicascola Boisduval — persicopbila, Bond — petasitidis — piceas — pini — pinicola . — porui — pruni — — Scop. — pruni folii — prinifex — pyraria . — pyri . — querciis — radicum — rapa) — retrolacteus, fossil — ribis — robovis . — rumicifex — rumicis . — saliceti . — salicis — salicivora — saligna . — sambucaria — sambuci — scabiosa; — sedi — serratula) — sorbi — stellarias — subterranea — tanacetina — tilia) — transparcns, fossil — tremula) — trirboda — tuberculata — ulicis — olmariffi — urticaria — va.stator — viburni . — viciaj — vimiualis — vitis — xylostei . Anohonatoa dorsuosus, fossil Aploncura leutisci Arcbcnteron Arcbilacbnus pcnnatus, fossil », PAGE ", 17, 106 . ii, 16 i> 178 i, 178 • ii, 69 . iii, 58 * }}}' 50 . iii, 52 • ii, 44 ii, 64 i, 166 • H» 64 ii, 64 ii, 53 • .*!' 97 . iii, 62 . iii, 63 • ."' 15 . iv, 164 ii, 9 iii, 5fl ,71 • \\> 82 ii, 81 ii. 52 21 ; ii ,53 ii, 134 . iii, 54 • }}' 95 ii. 99 • ii, 55 • H» 90 i, 161 ii, 58 ii, 147 8; iv, 105 ii, 63 . iii, 34 • iv, 168 . iii, 81 • .!!' 114 . iii, 14 ii, 8] ,84 • .!' 134 ii, 50 ii, 15, 1 ii, 77 i, 190 . iii, 53 ii, 111 ii, 25 • iv, 177 . iii, 186 . iv, 133 . iv. 177 GENERAL INDEX. 215 Arctaphis populi Aristotle on the drone . Author's reservations as to M. Lichtenstein's theory tion of Aphides — on pupif ere of Lichtenstein Axolotl, transformations of Balbiani, E. G., general remarks on Aphides — generative organs of Aphides — hermaphroditism — hybernation of S. millefolii — — S. solid aginis — on mycropyle — on ovarian chambers — and Signoret on Puceron de l'erable — on number of sperm capsules Balfour, F. M. 0., on heredity and variation — on the buds of animals . Banks, Sir Joseph, on American blight Berzelius on nature of amber Bibliographic lists — general sketch Birth-rate of in Aphis . Blind Aphides, remarks on . i, 15 ; iii, 7 Boisduvalia latanise, Signoret on . Boussingault on honeydew — — large quantity on lime tr Bonnet, Chas., researches on Aphides Bowerbank, J. S., circulation in wings of insects Brachycolus stellarise Brandt, Alex., on anatomy of Aphides Brodie on fossil Aphides Broods, number of Buffon on nature of amber Cabbage hernia, cause of . . Callipterus, general characters of — alni — betularius . • — betulse - — betulsecolens — betulella — betulicola . ; — carpini — castaneae — coryli — juglandicola — juglandis — querceus — quercus — — identical -with Vacuna dryophila Camera drawings, foreshortened . Canada balsam as a medium for mounting Aphides PAGE # # ii, 140 . . iv, 106 of migra- . , iv, 72 , , iv, 73 • ii, 133 i, 67 ! iv, m !, et seq. i> 67—69 iv, 74 % iv, 75 f , iv, 129 ii, 6 ; iv, 122 ii, 128 iv, 122 iv, 134 % # iv, 108 # iii, 91 B iv, 160 . iii, 137; iv, 203 i 48—69 t , i, 79 , 68, 88, 124 ; iv, 86 , iv, 198 i, 41 rees iii, 36 i, 50 i, 37 ii, 146, 147 iv, 118 iv, 147 i, 83 • iv, 160 ii, 21 . iii, 12 , . iii, 31 . t iii, 14 , , iii, 15 , , iii, 17 , , iii, 17 , , iii, 15 . , iii, 19 . , iii, 26 , , iii, 17 , t iii, 32 ui, 40 , . iii, 24 . . ni, 21 ii of Hnxley ui, 23 i, Preface iv, 191 21(3 49 . iii 119 ■14, 55, 59 ii 49 iv 106 i 69 iv 107 iv, 109 iv 117 • iv, 109 . iv L06 iv 119 GENERAL INDEX. 225 Reproductive organs of viviparous Aphis . — — of the male Respiratory system Rhizobiina?, introductory remarks on — Passerini as to variability of species — J. Hardy on species in ants nests Rhizobius graminis ; see note on PI. OXXIX — helianthemi — jujubae — poas .... Rhizoterus vacca Rhopalosiphum, general characters of — berberidia — cicutaa . — dianthi . — lactucae . — ligustri . nymphaaas pastinaceaa — ribis staphyleae Riley and Monell on Aphis galls . Rostrum, great development of, in Aphides . Sacchiphantes abietis Salicine in some Lachninae — in some Chrysomelidae Salivary glands Schizoneura Americana . — corni — fodiens — fuliginosa . — lanigera — lanuginosa . Reaumuri, synonymous with Puceron de tilleul — ulmi — vagans ■ — venusta — blind larvae of — galls made by i, 45 — life history of ... iii, 81 — migrations of ... iii, 86 — subterranean habits of . . iii, 95 Schizoneurinae, characters of . . .iii, 80 — general remarks on iii, 81 Schizoneuroides Scudderi (fossil) . . . • iv, 178 Schmidberger on number of species . . . i, 7 Scblecbtendal on mounting Aphides for microscope . iv, 192 Schrank on Aphides . . . . . i, 56 Scudder, S. H , on Aphides in Florissant beds . iv, 173 — on palaeozoic insects . . • iv, 145 Segmentation in Insecta and Crustacea . . iii, 6 — of body in Aphides . . . • i, 19, 21 — of yolk . . . iv. 129, 133 VOL. IV. 15 PAGK iv, 116 iv, 122 i, 34 iii, 65 ; iv, 79 iv, 80 iv, 82 iv, 93 iii, 68 iv, 181 iv, 93 iv, 83 ii, 9 ii, 14 ii, 27 ii, 15 ii, 10 ii, 13 ii, 12 ii, 24 ii, 9 i, 187 iii, 121 i, 16 iv, 24 iv, 195 iv, 196 i, 33 iii, 91, 97, 103 iii, 107 in, 94 iii, 96 iii, 89 iii, 104 iii, 36 iii, 97 iii, 107 iii, 96, 107 iii, i, iii, iii, iii, iii. 226 GENERAL INDEX. Sequence, geological, of insect orders Sex in Aphides . Silk, secretion of Silkworm, botrytis in — muscadine in . — empusa Siplia maidis . Siphocoryne — caprese — funiculi pastinacese . — xylostei Siphonophora . — absinthii . — alliariffi — artemisise . — avellanaa . — carnosa — cerealis — chelidonii . — cichorii — circumflexa — convolvuli — cyparissise — diplanteriae — dirhoda — fragariaa . — granaria . — hieracii — jaceae — lactucas — longipennis — lutea — malvffl — mentbse — millefolii . — muralis — olivata pelargonii — pisi — polygoni . — rosse — — vur. glau — — parasites of — rosarum . — rubi — — rufous variety of — scabiosa) . — scropbulariaj — sisymbrii . — solidaginis — Bonchi tanaceti . tanaceticola i, 87 PAGE iii, 4 iv, 141 i, 100 ii, 19 ii, 19 ii, 19 iii, 116 n, ii, ii, ii, ii, i. 23 27 26 24 25 103 i, 154 i, 123 i, 155 i, 149 i, 144 i, 115 i, 121 i, 163 i, 130 i, 148 i, 113 i, 136 i, 132 i, 125 i, 114 i, 126 i, 153 i, 139 i, 146 i, 119 i, 136 i, 120 i, 127 i, 157 i, 164 i, 136 i,134 i, 123 i, 103 i, 109 i, 111 i, 150 i, 140 iv, 105 i, 112 i, 137 i, 160 i, 156 i, 161 i, 151 i. 159 GENERAL INDEX. 227 PAGE Siphonophora tussilaginis . . . i, 159 — ulmarise . . . . i, 134 — urticse . . . . i, 143 — vicise . . . . i, 190 — millefolii, Balbiani on the winter habitat of . iv, 74 — solidaginis, Balbiani on the winter habitat of . iv, 75 Siphonophoroides antiqua . . . . iv, 176 — simplex . . . • iv, 176 Siphuncle . . . . . . i, 22 Somites, number of . . . . i, 19, 21 Sorby on colouring matter in Aphides . . ii, 170 Spermatheca . . . . . . iv, 121 Spermatozoa . . . . . • iv, 127 Sperm capsules . . . . • iv, 128 — cells . . . . . i, 129 Spread of American blight .... iii, 91 Steenstrup on alternation of generations . . . iv, 138 Stemmata . . . . . i, 15 Stomata, where placed . . . . i, 21 Stomaphis quercus ..... iii, 62 — Ingall's notice of, in England . . . iii, 63 — Linnaeus on . . . . . iii, 64 — rostrum of . . . . i, 17 Stonesfield beds, insects in . . . iii, 3 Subterranean European Aphides, list of . . iv, 104 Sudden appearance and disappearance of Aphides . iii, 57, 58 Sugar, the manufacture of, suggested from honeydew . iii, 55 Supplementary males .... iii, 20, 39 Swarms of Aphides . . . . i, 80 Sycophancy or Paracletism . . . . iv, 95 Synopsis of" classification . . . . i, 9 — of Aphis ..... ii, 30 — general . . . . . iv, 1 — of Siphonophora . . . i, 102 Syrphidse . . . . . ii, 117 — Bonnet on . . . . ii, 119 — Reaumur on . . . ii, 119 Syrphus balteatus . . . . ii, 120 Tendency to suppression of wing veining . . .iii, 42 Tent-making Chalcids . . . . . ii, 85 Terminology . . • . . . i, 11 Tetraneura, general characters of . , iii, 131 — ulmi ..... iii, 131 — reported as feeding on grasses . . . iv, 72 Thelaxes, anatomy of the eye of . . . . iv, 14 — reproductive organs, description of . iv, Plate D — shelter sought in oak galls . . . iv, 13 — variation in wing veining . . . iv, 10 — dryophila . . . . . iv, 8 Thorax and adjuncts . . . . i, 18 Thornton on Phyllophorus .... ii, 127 Thysanura, fossil remains of . . . iii, 4 Toxoptera graminum ... iii, 135 225 GENERAL INDEX. Toxoptera aurantia? Trama, general characters of — fiavescens — pubescens — radicia . — troglodytes — — wiDged form . Transmission of Aphides by post, eVc. Tryonix rapae . Tychea, remarks on — eragrostidis — phaseoli — setariae . — setulosa — trivialia Vacuna dryophila, of Huxley, identical with Calliptevus quercus Vander Haeven on Periphillus Variation in wing-veining Virchow on legitimate hypothesis Viviparism in Aphides .... Walker, Francis, on the winged female of Trama troglodytes — also of Paracleus cimiciformis — also of Aphis subterraneus — on migrations of Aphides . Wallace, A. R., on climate as affecting colour of insects — inadequacy of heat alone to affect them — on sex affecting colour in insects Water lilies, destruction of, by Aphides Westwood, W. O., description of fossil insects Wings, hooklets, use of . — insertions of — nervures and cells of — venation of Xenoneura antiquorum .... Yolk-cord ..... Zizyphus jujuba, attacked by an Indian Rbizobius . PAGE . iii, 135 . iii, 68 . iii, 68 iii, 08 iii, 68 . iii, 68 iv, 1U5 • *X» 188 ii, 35 ■ ! v ' 86 iv, 89 • iv, 90 • iv, 88 iv, 87 iv, 86 s iii, 23 ii, 127 . iii, ;»2 ii, o i, 84 • iv, 105 • iv, lu5 • iv, 105 i, 73 • ii, 32 • ii, 33 ii, 84 i, 70 • iv, 147 i, 27 i, 27 i, 28 i, 27 iii, 3 iv. 117 iv, 181 PB1MTBO HY J. V.. ADI.AUU, BARTHOLOMEW CLOBX. DESCRIPTION OF PLATE D.* Reproductive Organs of the Viviparous Aphis. Fig. 1. — Portion of the pseudovarium of Siphono- phora pelargonii with some of its csecal chambers : a a, terminal chambers : each of which has become constricted in the midst : b, c, d s e, /, represent other chambers with their embryos in progressive stages of development. In f f the eyes have become differen- tiated, and the body shows incipient segmentation. The antennas, rostra, and legs are clearly marked. The ovisacs are immediately connected with the oviduct, one of which is indicated at h. The caudal ends of the embryos are all turned towards the vulva or genital opening. I could not clearly separate out the colleterial glands of this specimen, but one probably is shown as a blind sac near the base of the vagina at i. /<•, the alimentary tube, charged with nutriment, and ending in the rectum /. Only one branch of the oviduct is here represented, and some only of the ovisacs are drawn. In some species of Aphis the ovarian tubes number six on each side ; and, as each tube may consist of six separate chambers, full scope is afforded for the multiplication of the insect. Dissected under weak syrup, January 6th. Mag. 34 diam. Fig. 2. — One of the pseudovigerous tubes of Sipho- nophora rosce, much "magnified : a represents the apical chamber, containing several ovarian glands, one of which has been constricted off from the rest, and has become the germinal vesicle with its germinal spot. * Plates, A, B, and C, will be found in Vol. I. DESCRIPTION 09 PLATE l>. /> and c represent other pseudova, in which the mass has undergone a coarse segmentation : d, the fourth chamber, in whicli the pseudovitellus shows a partial differentiation ; e, the fifth chamber or ovisac, in which may be seen indications of a body-cavity (s) forming out of the blastodermic layer (j>) ; /, the last pseudovarian chamber, in which the embryo has become more advanced ; p, part of the procephalic lobe of the blastoderm ; ?/, yolk-mass or pseudovitellus ; r, rudi- mentary fold of the abdomen ; o, rudiments of the foetal pseudovum, which occurs thus early in these insects. Mag. 112 diam. The details of this sixth chamber are after Prof. Huxley, but an error occurs in my present figure as to the position of the head, which, as before said, should have been turned in the opposite direction. Both Huxley and Brandt have noted exceedingly line ligaments proceeding from the free ends of the apical chambers of the pseudovaria. Such ligaments have not been observed, I believe, in the organs of the true female. These pseudovarian ligaments would seem to have some free intercommunication with the corresponding tubes (?) of the cajca situated at the other side of the Aphis. Their omission in this figure does not argue their absence in the living insect. (Fide Huxley, 1. c, p. 199.) Fig. 3. — Similar parts of the ovigerous tube of Ghermes abietis. These ovisacs are very numerous, and number more than one hundred. The peculiar cord observed and described by Huxley in " Vacwna dryophila" (Callvpt&rUS quercus?) is here readily seen at h. This cord is better seen in Plate V. Pig. 4. — The forceps-like appendage at the tail of Ohermes la/rids, employed by the insect in arranging her eggs. Both figures = 52 diameters. Pig. : ».— Much magnified apical chamber of Myzus i>< rsiar, showing several large nucleated cells or clear vesicles, as al /and at//. These consist of periplastic and endoplastic layers. One of these at a time de- DESCRIPTION OF PLATE l>. scends and becomes differentiated into the pseudoviun. The rest remain dormant, are absorbed, or perhaps they constitute the " Wanderelemente " of Dr. A. Brandt. 295 diam. (Fide Brandt, ' Ueber das Ei,' p. 51.) Fig. 6. — A germ extracted from its chamber and treated with acetic acid. It has no pseudovitelline membrane : v, clear vesicle, with its endoplast or nucleus ; m, blastoderm ; //, pseudovitellus with granules. After Huxley. PLATE D - 4/- J v ■ y ■ : 6 ~) is) / -;-' w i oductive organs of Lk_e DESCRIPTION OF PLATE E. Reproductive Organs of the Oviparous Aphis. Fig. 1. — Reproductive organs contained within the last four segments of the body of Oallvpterus quercus : a, left half of the oviduct, the elastic walls of which are composed of numerous circular transverse muscular fibres. The internal longitudinal fibres are not here seen. Shortly after the union with the right half of the oviduct a short vaginal tube is continued down- wards. This last ends in a wide-mouthed vulva, the entrance to which, and walls also of the vagina, are effectively controlled by fasciculi of muscles ; three on either side, so disposed that by their contractions the vagina and its entrance can be reduced to a narrow slit, and thus closed, e e, colleterial glands which end in attenuated ducts. These — the muciparous glands of other authors, anastomose into the walls of the vagina, into which passage they pour their lubricating secretion. The glands are large, very tough, and easy to be seen. Above these, but less obvious, is d, the spermatheca or pouch for storing the spermatozoa or male cells. Balbiani says that the intromittent organ of the male penetrates into the spermatheca. I could not certainly trace the insertion of the duct into the vaginal walls, but Morrens, Huxley, and Balbiani locate it above the insertion of the colleterial glands. Besides these organs, I have been able to note that the large trumpet-mouthed nectaries in this species DESCRIPTION OF PLATE E. end in capacious tubes, with corrugated walls. These taper as they pass downwards ; and their delicate ends apparently terminate in the free fluids of the abdo- minal region, and in spots largely charged with oil globules: />, vulva; c c, fasciculi of muscles attached to the vagina ; e e, colleterial glands and their ducts ; d, spermatheca ; //, nectaries or cornicles; y, part of the alimentary canal, which here takes the form of a loop before its final descent to the tail ; h, Cauda. 112 diam. Fig. 2. — Nearly similar parts from another specimen of Gallvpterus quercus ; but drawn in situ and without compression, o, a large ovum, which has entered the upper part of the dilatable vagina v, on its passage towards b, the vulva. The liquid from the muci- parous or colleterial glands would seem to affect the egg shortly before its expulsion. Probably these organs (c c) secrete part of the tough constituents of the dark shell, which hardens after exposure to the air. 52 diam. Fig. 3. — Portion of a same insect under the com- pressorium. The colleterial glands {<• <■) are flattened so as to show their transparent muscular walls. On continuing the pressure on the specimen used, a short membranous ovipositor was protruded, which was found capable of retraction within the body- cavity by the action of two bundles of muscular fibres seen at //. At the same time a stream of spermatozoa (s) diffused itself through the weak aqueous glycerine which bathed this specimen. The abdomen contained ten eggs in a forward stage of development. In another example I counted thirteen. In the Aphidian genera low in the scale, only one egg is produced by the perfect female. 53 diam. Fig. 4. — Magnified view of one of the colleterial glands. Its cavity contains folds of an excretory membrane, from the walls of which the pouch is ailed, as al ;/ and w; /■, excretory passage. Fig. 5. — Pari of the muscular coal of the last viscus, DESCRIPTION OF PLATE E. which shows the numerous bundles of muscular fibre composing its walls, g and w as in fig. 4. 150 diam. Fig. 6. — A portion of the same coat separated out with the needle. 295 diam. Fig. 7. — Apical part of an ovarian caGCum, from the lower part of which, at c, an ovum has escaped. Eventually one of these nucleated, but immature glan- dular bodies (a b) will descend towards the cavity (c) and develop into another vesicle with its ectoplastic and endoplastic layers. The walls of the cyst are studded with epithelial scales, as shown at d d. Magnified 100 diameters. A more highly-magnified portion of such a wall enclosing an ovum may be seen in Plate F, fig. 2. All the preparations in this plate here described are from dissections of the oviparous female of Galli- pterus quercus ; numerous living examples of which were kindly sent me, early in October, from East- bourne, by Mr. Foran. The insects were dissected after treatment with various fluids, such as chromic or acetic acids, alcohol, weak glycerine, petroleum spirit or solution of common salt, employed either to harden the tissues or for the purpose of rendering the parts more evident by vary- ing their refraction of light whilst viewed under the microscope. Notwithstanding the more elaborate treatise by Prof. Huxley on the anatomy of the oviparous female of Aphis, I offer the following contributions : and with the general remark that my camera-lucida drawings confirm me in the belief that what the last author has advanced as applicable to the species he examined, is in agreement with Callipterus quercus, the diagnosis of which occurs in Vol. hi, page 21 of this Monograph. PLATE E 5. " g 9 " c "' is - ! d 6. ... . c / . . Y • - % : i ri.B.B^cUW, Reproductive, organs of the O vi p arous Ap 1 1 i s . DESCBIPTION OF PLATE F. Oviparous Aphis. Fig. 1. — Three chambers of an ovigerous fascicle, re- duced from a figure by Huxley : e, epithelial layer ; g g\ inner capsules of ovarian glands, which, originally round, have by the natural lateral pressure become elongated ; c, cord-like secretion of ovarian gland ; v, germinal vesicle of a nascent ovum in the terminal chamber; v', germinal vesicle of the second chamber of the caecum. Fig. 2. — Portion of the walls of the ovisac, with its epithelial cells, enclosing a nearly ripe ovum : y y vitelline mass of the egg; s, clear space surrounding the yolk (zona pellucida ?) ; e, epithelial coat of ovary. From Gallipterus quercus. 130 diam. Fig 3. — One branch of the oviduct of another example of the same species : v, vaginal tube ; c c, colleterial glands ; s, probably the insertion of the spermatheca not here visible. The ovarian caeca in the oviparous female are not so numerous as are the pseudovaria of the viviparous female. Although only six separate branches are visible in this figure, probably eight, viz. four on each side, are the correct number; at k the constriction of the apical caecum has com- menced. Dissected in petroleum spirit. 40 diam. Fig. 4. — Ovarian caeca with part of the alimentary canal of the pupae of Chermes abietis. The embryonic masses forming the incipient eggs are green, and show different conditions of maturity. In some caeca the apical chamber is almost obliterated, but in all, the glandular masses are floating in a colourless fluid. DESCRIPTION OF PLATE F. The alimentary tube is of a violet shade, and under a high magnifying power shows its surface to be paved with epithelial scales: g , -)■:. c 70. V - > - ' ^ 1 G- B. Bii^kton fib . ■ organs of the Ovi] ApJais . DESCRIPTION OF PLATE G. Reproductive organs of tfie Male Aphis. Fig. 1. — Profile view of the last abdominal rings of the male of Drepanosiphum platanoides with the ex- serted penis : «, anus situated immediately under the cauda ; r, the copulative armature and part of the horny ring used to secure contact with the female ; o o, opercula closing the genital opening ; k, the outer sheath of the penis, which forms the inner lining when the organ is retracted within the body-cavity ; //, folds of the inner tube, which conversely becomes the outer lining on retraction ; m, meatus penis, and part of the ejaculatory canal ; s, seminal and muciparous ducts. The walls of the inner tube of the penis are more voluminous than the outer, and these folds (ff) are obliterated when the organ is turned inside out. Fig. 2. — The same organs represented in plan, and seen in situ before their protrusion, with the secretory glands attached. The same lettering, as a rule, applies to both these figures : c, the copulative sac ; j, the ejaculatory tube ; d, deferent duct ; v, vesiculse semi- nales ; g, muciparous glands with their ducts ; p, testes or sperm-capsules ; g, genital opening. Fig. 3. — View of a testis with included sperm-cysts in different conditions of maturity : a?, immature cyst with sperm cells before they have developed filaments ; y shows a cyst with the spermatozoa disposed in bundles. Fig. 4. — A circular cyst more highly magnified, the filaments of which (?/) are ranged in parallel order. These four preceding figures are after Balbiani. DESCRIPTION OP PLATE G. Fig. 5. — A fascicle of testes dissected from the winged male of Lachnus pinicola in October, showing the presence of similar sperm-cysts at u and v. Fig. 6. — Highly magnified view of the apex of the penis of the winged male of Dryobius roboris, showing the different folds of the organ when protruded : m, meatus penis ; c, inner fold, as in fig. 2, which by its eversion has become the outer fold. In a similar manner j, as in fig. 2, has become the inner fold of fig. 6 ; d, duct from vesicula seminalis ; p, part of testis which has descended ; s, spermatozoa ; s", the same magnified 206 diameters. Their motion in the liquid was very feeble, and I could detect no filaments. Fig. 7. — Part of the male organs of Aphis dirhoda dissected in weak syrup : c, Cauda ; r, armature ; p, hooked penis ; m m, muciparous glands ; a, alimentary tube ; 1 1, testes connected with the vasa deferentia v. Fig. 8. — Single branch of testis from the winged male of Aphis opiina : t, t, sperm capsules ; v, seminal vesicle ; m m. muciparous glands. The excretory duct was not visible in this preparation. PLATE G- . - ■ ■ - , ' ■ I v - ■y - G-.B. Bitcfcton djt Reprodu DESCRIPTION OF PLATE H. Development of the Ovum in Aphis. Fig. 1. — A young ovum before segmentation has commenced, b. body of ovum ; g, germinal vesicle ; s, germinal spot ; n, nucleolus. After Haeckel. Figs'. 2, 3, 4, 5. — Ova in different successive stages of segmentation or division into 2, 4, 8, &c. cells until the mulberry- form or morula-stage of Haeckel is at- tained. The cell ultimately forms a double wall, enclos- ing a central cavity with blastospore. Fig. 6. — An ovum in process of fecundation by the intrusion of the spermatozoa, by the action of which segmentation commences : z, zona pellucida ; g, ger- minal vesicle ; n, spot and nucleolus ; sp, spermatozoa just before penetration into the body of the egg. The foregoing six figures, after Haeckel, are dia- grammatic, and are only generally applicable to Aphides. Figs. 7 and 8. — Polar cells and micropyles (?) of the ova of Lachmis longipes : 1 1, represents the spindle of Fol (?) formed from the metamorphosis of the germinal vesicle ; s s, stellate body forming part of the eminence rising out of the chorion ; r r, gelatinous investment of Huxley. This would appear to be the polar appendage of Balbiani. Treatment with acetic acid. 112 diam. Fig. 9. — Polar mass and appendage of the ovum of Aphis persicce : a, probably represents the spindle of Fol; p, the polar mass studded with green cells. The appendage is surrounded by an epithelial layer. After Balbiani. DESCRIPTION" OF PLATE H. Fig. 10. — Posterior appendage or micropyle of Apbis, treated with weak potash solution : e, eminence rising from the chorion h ; f, appendage containing rod-like bodies ; r, gelatinous investment. After Huxley Fig. 11. — Ovum of Phyllaphis fagi soon after it has been laid. It is sufficiently transparent to show (r) the coarse segmentation ; m, polar opening or micro- pyle. 40 diam. Fig. 12. — Part of the ovum of GaUipterus quercus treated with acetic acid : s, annular congregation of cells forming a polar mass or pronucleus (?), vide Balfour, 1. c, p. 59. Fig. 13. — Centrolecithal* segmentation of the ovum of Siphonophora rosce. Ovum is still in the ovisac. n 7i, two clear nuclei have appeared, and they are surrounded by v 9 the vitelline mass enclosed in a proto- plasmic layer, I. Fig. 14. — The same more advanced ; in which the protoplasmic layer has been differentiated into a series (c c) of columnar cells ; p t the pole of the blastoderm, which has no share in forming the embryo. These two figures are copied from Metschnikow. Fig. 15. — The germ-cup or gastrula-stage of Haeckel, in which the blastoderm has become dented in, and the original single membrane has become two. The ends have approximated to form the intestinal cavity or archenteron; and h, the stomodamm, blastopore, or primitive mouth ; e, the entoderm or hypoblast ; /*, the ectoderm or epiblast. Fig. 10. — A much magnified view of the ovum of Aphis persicai still enclosed in the ovisac. It has begun its incipient segmentation. At the pole (w) a depression or invagination encloses a clear yellow space, which is comparatively free from yolk granules. The vitelline membrane is seen enfolding, r, the coarsely granulated yolk, which last is passing into the mul- berry-like segmentation. The granules congregate * From Klvrpov, a centre, and X^icvOoc, lecythus, an oil vessel. This kind of segmentation is almost confined to the Arthropod a. DESCRIPTION OF PLATE H. round the polar space at s : m, the micropyle or polar appendage. Fig. 17. — Ovum of Siphonophora rosce showing the rudimentary organs of the embryo within : a, abdo- men ; /, visceral fold of the foetal integument ; g, genital gland ; s, side-plate (Seiten-platten) bordered by a row of cells, partly seen in section ; v, yolk vesicles ; l l J 2 1 3 , analogues of legs ; p, parietes or walls. After Brandt, who adds the following remarks to the description of his figure : " Die Bildung des Dottersackes nebst der mit dersel- ben verkniipsften Umrollung oder Dochung des Embryo und seine Queraxe beruht auf einer selbstandigen con- traction des Parietaten Blattes der Embryonalhiille." Vide Dr. Alex. Brandt, " Beitrage zur Entwicklungs- geschichte der Libellulen und Hemipteren." ' Mem. Acad Imp. Sci. de St. Petersb.' t. xii, ser. 7, p. 33. PLATE H. 5. 4- 4g> y^- Nif 2 ! > |j J ' ' ; sy>. ■* 9 75 -Vy 73. ■ ■• ■ ■ 9 16. ■ —A- IV 14 : - 1 - • ... p 19. ' ^8. r 7 *■ _^» -> . z, > I V _.. _ .JO -- o ----- s c-- C.B Bucktim dei.etUth.. WestXi . Ovum, of Aphis DESCRIPTION OF PLATE I. Embryology op Aphis. Fig. 1. — Unborn foetus of Aphis pruni. The limbs have been disengaged from the folded mass by needles. Fig. 2. — Another specimen, which has not been so unfolded : c c, of both figures, represent the cephalic lobes. Fig. 3. — Unborn embryo from the pseudovarium of Lachnus viminalis : c, head ; g, the rudiment of the pseudovaria, below which may be traced the antenna?, the legs, and the elements of the rostrum. Fig. 4. — Another and less-matured embryo. Both these forms are invested in the membranes afterwards to be thrown off at birth, c and g represent the same organs as before. Fig. 5. — Unborn foetus of Pemphigus lactucarius. These embryos have been toughened by soaking in dilute alcohol, a, antenna ; r, rostrum ; I, legs. Fig. 6. — Another example, drawn when nearly ready for birth. Similar parts may be distinguished as seen in the former examples : I, legs ; r, rostrum. Fig. 7. — Embryo of the same species, which would have furnished the pupal, and finally, the alate form. In this unborn condition the rudiments of wing-cases may be traced. Conditions analogous to the caterpillar are thus fulfilled on the foetus within the body of the parent, w, wing case. Fig. 8. — Embryo of Pemphigus, just born, showing that the antenna? (d), which are very simple in articu- lation, are disengaged before the other limbs. Fig. 9. — A much-magnified front view of one of the late broods of Pemphigus lactucwius. a, antenna ; r, rostrum ; I, legs. These examples are figured to exhibit the very diverse forms of the embryos of different genera and even broods of Aphis. Perhaps they may be suggestive of primaeval types and represent an ancient ancestry. Fig. 10. — Embryo extracted from the pedunculated DESCRIPTION OF PLATE I. pseudovuiii of Chermes laricis, hardened previously by weak alcohol. The young are to be found here in a very perfect condition of development ; the antennae are well articulated, and the three remarkably long rostral setae are very conspicuous. This specimen was taken from a pale yellow egg, which had not been much darkened by exposure to the air, and probably, therefore, it had been recently deposited. It may perhaps be inferred that, as the young in these eggs are in so forward a state just at the time of laying, there is some approximation to the ordinary viviparous production of the unfecundated egg. I have not been able to discover the fecundated egg (the true ovum) of Cltrrmrs ; but we know that in allied genera of Aphis it is very large and often single. The (pseudo-) ovarian caaca of Chermes probably amount to one hundred. Fig. 11. — Embryo from the pseudovarium of Aphis pelargonii, reduced from Prof. Huxley's figure and seen in profile : e, alimentary canal, taking a curved form and ending at the anus a; lb, labruni ; . — Small apterous male. Fig. 7. — Oviparous female of relative size to the last insect, with two ova. PliATE CX* c:.s B efcZtffc. - Tliel axe s drvo p] . PLATE CXVI. (Page 16.) Glyphina pilosa. Fig. 1. — Larval form covered by its mealy coat. Fig. 2." — Winged viviparous female. Fig. 3. — Head and antenna of the same insect. Fig. 4. — Part of tibia and tarsus. Claws double. ■€>' Chermes abtetis. (Page 24.) Fig. 5. — False cones of the spruce fir, caused by the punctures of the queen mother Chermes ; drawn of the natural size. One of these cones has been cut through after the insects have escaped, thus showing the empty cells, a. A portion of the original shoot, at the base of which the distortion has commenced. The winged Chermes are drawn of their natural size. PLATE CXVT. V . i ' \u^kix>n oW. iL 7£th, West Ne-wrrvarL & C iw-e hirta pilosa i - 4- . CJiewned nbielis 5 . PLATE CXVII. Glyphina betum. (Page 17.) Fig. 1.- — Larva seen from the underside. Fig. 2. — Pupa of the same insect. Fig. 3. — Imago, with some of her brood just born. One of these has not yet disengaged itself from the enshrouding membrane. Fig. 4. — Antenna of the apterous female. Fig. 5. — Antenna of the imago. The joints are much ringed or cupped. Cheemes corticalis. (Page 23.) Fig. 6. — Cocciform larva denuded of her downy coat, and showing her long prehensile seta?. Fig. 7. — Pupa. The wing-cases are much detached at the points, and are not agglomerate. Fig. 8. — Larva surrounded with cotton-like fibres, and also covered by bands of a mealy powder. She is arrangiDg her eggs of different colours. Pig. 9. — Antenna of the imago drawn on Plate CXVII Us, fig. 1. Fig. 1<>. — Tarsus with claws and foot-discs. PLATE CXVIl . B BucWn dtl.ttUth.. Wt<.v, Aetvm^r.&e Co \mt,. GlyphLna betulse 1—5. Cher mes corticaJis 6 LO PLATE CXVII Us. Chermes coeticalis. (Page 23.) Fig. 1. — Winged viviparous female. Fig. 2. — Abnormal wing from the same species, showing a variation in the venation. The 3rd oblique vein has united with the 2nd oblique. The cubitus of the lower wing is very coarse and has become cellular. Fig. 3. — Head and antenna of the larva (drawn on Plate CXVII, fig. 6). The minute terminal bristles show an approximation to Coccus. Ciieemes pini. (Page 40.) Fig. 4. — Larva seated on her pedunculated eggs. Fig. 5. — A similar larva denuded of her woolly coat by its solution in ether. Fig. 6. — Antenna of the same insect. Thelaxes. Fig. 7. — Abnormal upper wing of Thelaxes dryophila. Page 11. Fig. 8. — Abnormal upper and lower wings of another example of Thelaxes. Such a complication of veining might be caused by a cross breeding; or otherwise it might show some forward movement in development. Fig. 9. — One cornicle or nectary of Thelaxes dryo- />li i In separated from the other organs of the body. d. The mouth is expanded by circular muscular fibres. A long tube from this mouth is carried backwards into the body-cavity, and is lost in the viscera of the insect. Similar organs are seen in situ on Plate E, fig. If. Fig. 10. — Portion of the eye of the larva of Thelaxes, showing the rod-like bodies at e, and three simple lenses in advance at /. These rods appear to be arranged differently from those connected with the ordinary faceted eyes of insects. PLATE GXVU. l Bis) ! ^ ^ . x C° imp irmes corticalis 1—3. Qb.erm.es pini i 6 Tkelaxes dry* 7—10. PLATE CXVIII. Chermes abietis. (Page 2-4.) Fig. 1. — Larva taken out of a pseudo-cone of the spruce fir, with several of the faecal (?) globules noted in the text. Fig. 2. — Underside of the pupa which develops from the last insect. Fig. 3. — Upper side of the pupa. Fig. 4. — Imago with expanded wings. The broad cubitus and large coreaceous stigma may be noted. Fig. 5. — Alate female with wings at rest, folded horizontally. Fig. 6. — Dead body of the same attached to a leaf of spruce fir. The dry body serves as a roof and protection to the young which have been hatched beneath it. Fig. 7. — Head and antenna of fig. 4. Fig. 8. — Minute male of Chermes abietis showing at $ the remarkable development of the intromittant organ. Fig. 9. — Underside of the head of male, showing that in this species the male is not wanting in the mouth parts. Fig. 10. — Tarsus and claws of male. PTjAT£ C XV LIT. X V . •^ **v "Q O 7. X .B BvuJctori 'M "J I'"' W/isb2tewmoai g-C?i*ni> (liermes a_bietis PLATE CXIX. Chermes abietis. (Page 24.) Fig. 1. — Half section of a portion of a twig of the spruce fir, showing how, by irritation of the rostrum of the queen Chermes, an approximation of the opposite sides of the leaflets is affected at b. A cavity results at a which encloses the insect, and finally the leaves form one of the cells of the false cone as seen on Plate CXVL Fig. 2. — Appearance of one of the cells of the false cone after one of the scales has been raised. All the pupse are seen ranged side by side with their heads outwards, ready to escape after their change into imagos. Chermes laeicis. (Page 33.) Fig. 3. — Underside of a larva, just after it has moulted or shed its skin. The long hair-like seta) proceed from the rostrum at r to the empty sheath at s on the slough. This kind of retaining cable is to be seen also in other species of Chermes. Fig. 4. — Portion of a larch leaf, on which the foun- dress is seated surrounded, at o, by her pedunculated eggs. These are of different colours, according to their conditions of maturity. At t a globule of resin is seen partly covered by cotton. This small drop is very constantly seen, wherever the Chermes fixes her station. Fig. 5. — Antenna and proboscis of the last figure. Figs. 6 and 7. — Magnified views of the rostrum and foreleg. Fig. 8. — A tuft of pedunculated pseudova, cleared from the cottony covering. Fig. 9. — Antenna of tlio winged female, showing the annulated f orm of the principal joints. PLATE CXTX . ' n3t: ■ B.Budeton. dieL et Jitk CiierjrM.es SLbietas" 1 la: 'l CIS 3 PLATE CXX. Chermes laricis. (Page 33.) Fig. 1. — Apterous female which has been hatched from a pseudo-egg of the foundress, t. Secretion from one of the abdominal pores. Fig. 2. — Pupa. The apical ring has three sharp terminal spines. Fig. 3. — Antenna of fig. 1. Fig. 4. — Imago showing the peculiar manner in which the upper cubital vein takes its origin. Chermes atratus. (Page 39.) Fig. 5. — Imago. The great development of the thoracic region here seen is a characteristic of Chermes. Fig. G. — Eye and antenna of the last. The deeply ringed character of the joints, and the auditory (?) tubercles at b are worthy of note. PLATE CXX ClaernLes la „ — a.tra.tu_s 5 6 . PLATE CXXI. Phylloxera punctata. (Page 45.) Fig. 1. — Queen Aphis, the produce of the single egg laid by the true female. This insect has just passed a pseudovum which she is ranging in an inner circle by means of her blunt ovipositor. The corru- gated state of the egg envelopes shows the forward condition of the enclosed embryos. Fig. 2. — A larval form which has subsequently hatched from one of these eggs. Fig. 3. — Upwards of 70 pseudova, showing the manner in which the eggs are disposed under an oak leaf in concentric circles. The larva of a small Myina is represented devouring these eggs. Fig. 4. — The imago, showing the pseudova within. This insect shows no characteristic frontal tubercles. Late in the autumn the second brood of alate females occur, and these contain eggs of different sizes, dis- closing the true males and the females. PLATE CXXI. ■A Newman & i ' Pliylloxera pui-. ba.1 PLATE CXXII. Phylloxera punctata. (Page 45.) Fig. 1. — Under side of the pupa. Fig. 2. — Larval form of a later generation. Fig. 3. — Pupa of the same. Fig. 4. — Head and antennas of the imago, showing the complete visual system of ocuius, ocellus, and stigmata. The ringed character of the third joint without any tubercle is to be observed. Fig. 5. — Enlarged view of the underside of the head of the fundatrix (fig. 1 of preceding Plate), d. rudi- mentary eye composed of only three simple lenses. b. Lab rum attached to the 4- jointed rostrum lying between the coxae. Fig. 6. — Foot of the same insect, showing the double claws, d, the pulvilli or foot pads, and capitate bristles. Phylloxera vastatrix. (Page 57.) Fig. 7. — Male. As this insect was four days travel- ling by post it probably is somewhat drier and shorter t han those taken immediatelyfrom the vine. The insect, however, was quite lively when drawn, e represents the size it bears relatively to the perfect female below. Fig. 8. — The female with her single fecundated egg. Those two figures are drawn to the scale of the larvae in Plate CXXV. PLATE cxxir. *G* ^M&- ■ > Cr.B.Burkten .. ■.wman SLC?-L™p. Plxylloxera. punctata 1 — 6 „ vastatrix 7 — 8 PLATE CXXIII. Phylloxera quercus. (Page 49.) Fig. 1. — The queen; her whole body is studded with tubercular processes with large heads. She surrounds herself with irregular patches of shining green eggs. Fig. 2. — The same insect seen from the under side. Fig. 3. — Smaller and smoother individual taken in company with the last. Fig. 4. — Imago showing the porrected vertex. Fig. 5. — Head and antenna of the same. Fig. 6. — Antenna much magnified to show the long apical channel c covered by membrane, and the circular pits d on the second joint, a. Porrected tubercles. o. Ocellus. Fig. 7. — Tarsus and claws of imago. Fig. 8. — Antenna and tubercles of Fig. 1. b. Tubercles. Fig. 9. — Simple eye of the last insect. Fig. 10. — Part of the under side of an oak leaf showing the yellow patch caused by the Phylloxera. The eggs and larva? are in situ. For purposes of comparison I figure : Fig. 11. — Antenna of Ph. punctata. Fig. 12. — Antenna and horny processes of the larva of Ph. coccinea. Fig. 13. — Antenna of the imago of Ph. coccinea. \ ( • PLATE CXXITl &4 ' & >,. ' ; . - . . n. s fr"' fear^ : ■•«&-" . G b.BocKot ,.;•■ WestJTewmo* * C? imf ^Pliylloxera, au_ercils PLATE CXXIV. Phylloxera vastatrtx. (Page 57.) Fig. 1. — Winged female containing a pseudo-egg, out of which the male or the female would proceed. The clear space round the ovum represents the rudi- ments of the egg-envelope. This M. Lichtenstein regards as a true pupal covering, and accordingly he calls this winged insect " Pupifer." Fig. 2. — A vine leaf, natural size, studded with leaf- galls. These galls have been raised by a previous winged form, which issued from the ground earlier in the year. Fig. 3. — Antenna of fig. 1. Fig. 4. — Apterous female bred on the root as seen in situ in fig". 5. Fig. 5. — Fragment of a larger root of the vine, infested by larvse and their eggs. This is the most destructive form of the pest in Europe. A section of one of the above leaf-galls may be seen in the next Plate (fig. 2). Prof. C. Riley groups the aerial forms under the head Gallicola, and the subterranean forms under that of lladicicola. PLATE CXXW. t.iV' fc. Ha ^r • . Pliylloxera a . PLATE CXXV. Phylloxera vastatrix (gallicola). (Page 57.) Fig. 1. — Foundress taken from one of the galls on the leaf, fig. 2 of last Plate. She is larger than the root varieties, and she contains many hundred eggs. Fig. 2. — Magnified section of one of the leaf -galls, showing the larvae of several generations surrounded by their ova. Fig. 3. — Antenna of foundress fig. 1. Phylloxera vastatrix (radioicola). Fig. 4. — Larger larva, taken from the root. She contained eight ova only. Fig. 5. — A different generation of the same. Taken early in July. Fig. 6. — Head and rostum of fig. 4. Fig. 7. — Under side of one of the larvae, feeding on the root fibriles. Fig. 8. — Claw of the same. These claws fold parallel, one beside the other, so as often to appear as if they were single. Fig. 9. — Profile view of larva (after Lichtenstein). Fig. 10. — Portion of a vine root, showing how the fibriles become distorted by blebs and swellings. Drawn natural size (after Licht.). The true sexes are drawn at PL CXXII, figs. 7 and 8. The diverse forms taken by these larvae after their moulting is remarkable. PLATE CXXV 17 va. s t a t r i x: PLATE CXXVI. Forda formicaria. (Page 83.) Fig. 1. — Larger apterous female taken whilst feeding at the roots of various grasses. Fig. 2. — A smaller and whitish variety, commonly found intermixed with the former insects. Fig. 3. — Another variety, probably a later genera- tion of the same species. Fig. 4. — Underside view of the head of fig. 1, show- ing the articulation of the antenna and the rostrum. Fig. 5. — Stool of grass, Triticum repens, under which there was a nest of Formica rubra. The roots pene- trated this nest, and the Aphides were feeding on these, as well as on the blades close to the soil, as drawn at a. PLATE CXXVII. Forda viridana. (Page 85.) Fig. 1. — Apterous form found under tufts of grass at Wooler in Northumberland. They tenant the nest of Formica fuliginosa. Fig. 2. — Rich brown variety found intermixed with the former insects. Tychea trivialis. (Page 86.) Fig. 3. — Apterous oviparous female taken under tufts of Poa annua, a. Antenna. Fig. 4. — Younger specimen of the same with ex- tended rostrum. Tychea setulosa. (Page 87.) Fig. 5. — Viviparous female. Fig. 6. — Another variety, probably part of a later brood, b. Antenna of the same. Fig. 7. — Variety found intermixed with the last. Fig. 8. — Young insect just after birth. All the examples of these insects were in company, and taken by Sir J. Lubbock in anthills at Becken- ham. PLATE OXXVII /t~f**o ' ^ I SI M; U * 1 ^k=ce: ; 7. G-.B.Bu.i .-., W,-.' efc Jift.. < ,0 i™p. F.or'da .viridaiLa 1-2. Tychea. trivialis 3-4;. Tychea setxilosa 5-8. PLATE CXXVIII. Ttchea setari^;. (Page 88.) Fig. 1. — Foundress (?) of the colony. Fief. 2. — Underside of the same. 2 a. Antennae. Fig. 3. — Later and more developed brood of the same. 3 a. Antenna. Fig. 4. — Matured individual. The altered character of the antennas (4 a) is to be noticed. 4 b. Tarsus and double claws. Tychea eragrostidis. (Page 89.) Fig 5. — Foundress of the colony. 5 a. Antennas of the same. Fig*. 6. — A later brood. 6 a. Antenna. ■.-.• Tychea phaseoli. (Page 90.) Fig. 7. — Foundress of the colony. 7a. Antenna. Fig. 8. — More developed individual of a later brood. 8 a. Antenna. plate cxxvnr. « \ ] I j i h . %m. - 21 5 - f i ^ V C5CLX5 A O 4|£f - ■ ■ I J ' ...-■ G-.B.BvuJctort Ad, „t 2itfi &.ra rubi f i our ru Aplii s a ubt err a.ne a. 2 . Trama ? 3. 'Psuna.cletu.s ' l 4- . PLATE CXXXI. Phylloxera punctata. (Page 45.) Fig. 1. — Apterous female from which the males and females are developed. Fig. 2. — Underside of the male, showing the oblite- ration of the rostrum, and the buccal projections at r. Fig. 3. — The female after she has laid her winter egg. Her body here consists of a mere membranous shell. The line p represents the size of the female as she would appear if magnified as much as the male, fig. 2, is drawn. APHIDES IN AMBER. Aphis (?) araneiformis. (Page 165.) Fig. 4. — a. Antenna, b. Last abdominal rings with the short Cauda and clavate nectaries. Aphis (?) hirsuta, (Page. 166.) Fig. 5. — e. Antenna. Lachnus (?) dryoides. (Page 166.) Figs. 6 and 7. — The upper and lower sides are shown and also the rostrum. Aphis (?) cimicoides. (Page 167.) Fig. 8. — -/. Antenna of the same. Lachnus (?) longulus. (Page 167.) Fig. 9. — cj. Antenna. Aphis (?) transparens. (Page 168.) Fig. 10. — h. Antenna, i. Upper and lower wings. The veining here shown is abnormal. The natural sizes are represented by lines. PLATE CXXXL --r i *p— i - Ji 7»\ ' ■»•;■' sf*" R '■V % ■V\ «/' 6 fe o ti p ■ ■■ ■ G S.Svjckton i<< . o u " Phylloxera punctata 1-3. — ' • ' » ~- u after Berendi PLATE CXXXII. FOSSIL APHIDES. Aphis (?) longicaudatus. Fig. 1. — Winged female. From Amberieux (Ain). After Milliere. [M. Pierre Milliere, in 1853, published in the ' Ann. Soc. Ent. de France,' 3 ser., t. i, pp. 9 — 11, pi. 3, fig. 2, a description of a fossil insect which was embedded in the " Schiste Marneau," near Amberieux (Ain). He calls it an antediluvian Aphis, and from " les deux appendices, places a l'extremite de l'abdomen " (which are only cornicles), he styled it Aphis longicaudatus.] Aphis (?) macrostyla. (Page 169.) Fig. 2. — Winged viviparous female. Lachnus (?) bonneti. (Page 170.) Fig. 3. — Winged viviparous female. Aphis (?) valdensis. (Page 118.) Fig. 4. — Wing and apterous insect. Fig. 5. — Shows these specimens in the matrix of the natural size. Purbeck limestone. After Brodie. Aphis (?) delicatula. (Page 170.) Fig. 6. — Portion of a winged female. Aphioides succifera. (Page 164.) Fig. 7. — Apterous specimen from amber. After Motschulsky. Lachnus (?) pectorosus. (Page 171.) Fig. 8. — Winged viviparous female, a. Antenna. Aphis (?) morlotti. (Page 171.) Fig. 9. — Winged female. Aphis (?) pallescens. (Page 170.) Fig. 10. — Winged female. Fig. 10a. — Another specimen. Lachnus (?). (Page 172.) Fig. 11. — Fragmentary specimen. This and figs. 2, 3, 6, 8, and 9 are from Radoboj, after Heer. Pemphigus (?) bursifex. (Page 172.) Fig. 12. — Ancient poplar leaf, from the (Eningen beds, with a gall-like swelling, probably the work of a Pemphigian Aphis, b. A magnified view. The small puncture is supposed by Professor Heer to have been formed by some gnat-like parasitic insect. PLATE CXXXIL - J^\" a / G.BBuAtcr Id efcKtfi West Newnnxii. & C ? imp Possil Aphides. after J3rodj.c an J Hear PLATE CXXXIII. Fossil Aphides, after Scudder. Fig. 1. — Siphonopkoroides antiqua. (Page 176.) Fig. 2. — Siphonophoroides simplex. (Page 176.) Fig. 3. — Arcliilachnus pennatus. (Page 177.) Fig. 4. — Anconatus dorsuosus. (Page 177.) Fig. 5. — Scliizoneuroides Scudderi. (Page 178.) Fig. 6. — Pterostigma recurvum. (Page 178.) PLATE CXKXni 1 J i / W G.B.Blicfcton aUl eh hih. West Newmouit 0?im*> Fossil Aphides. after S.H. SciUJULer . PLATE CXXXIV. Cerataphis latani^e. (Page 198.) Figs. 1 and 2. — Apterous female and part of another, surrounded by discs of wax. They are fixed to a por- tion of an orchis leaf. Fig. 3. — Another individual, placed so as to show the underside, and the position of the rostrum. The disc has been removed. Fig. 4. — One of the young born from fig. 1 . It has passed a moult, and the wax disc has commenced to grow. Fig. 5. — Inferior view of the head of fig. 1, showing at g the wax-glands ; at h the small horns ; and at a the antenna, much magnified. Fig. 6. — The winged -viviparous female. The lower wings are faintly drawn in their probable position ; they were lost in the specimen from which the draw- ing was taken. Fig. 7. — Head, antenna, and fore leg of the imago. Fig. 8. — Magnified fore leg, showing the tarsus and claws. Fig. 9. — Cauda and minute papillae, from the same insect. Fig. 10. — Part of the base of a palm-leaf, studded with numerous larvae of Cerataphis latanice. Drawn of their natural size. PLATE CXXXJV. G-.B Biickto-.t del.et Uth . West Newman- & C° imp Cerataphis latamee. •F > 1 ** * m mm % ^-■zt- > mtm ::. mtm :i m