FOOTNOTES

FOOTNOTES1A most minute and exact description of the newly hatched larva ofChionobas Aëllois given by the American entomologist, Samuel H. Scudder. Ann. Soc. Ent. de Belgique, xvi., 1873.2I am aware that this certainly cannot be said of philosophers like Lotze or Herbert Spencer; but these are at the same time both naturalists and philosophers.3“Über die Artrechte desPolyommatus AmyntasundPolysperchon.” Stett. ent. Zeit. 1849. Vol. x. p. 177–182. [In Kirby’s “Synonymic Catalogue of Diurnal Lepidoptera”Plebeius Amyntasis given as a synonym andP. Polysperchonas a var. ofP. ArgiadesPall. R.M.]4“Die Arten der Lepidopteren-GattungInoLeach, nebst einigen Vorbemerkungen über Localvarietäten.” Stett. ent. Zeit. 1862. Vol. xxiii. p. 342.5[Eng. ed. W. H. Edwards has since pointed out several beautiful cases of seasonal dimorphism in America. ThusPlebeius Pseudargiolusis the summer form ofP. Violacea, andPhyciodes Tharosthe summer form ofP. Marcia. See Edwards’ “Butterflies of North America,” 1868–79.]6[Eng. ed. I learn by a written communication from Dr. Speyer that two Geometræ,Selenia TetralunariaandS. IllunariaHüb., are seasonally dimorphic. In both species the winter form is much larger and darker.] [Selenia Lunaria,S. Illustraria, and some species ofEphyra(E. PunctariaandE. Omicronaria) are likewise seasonally dimorphic. For remarks on the case ofS. Illustrariasee Dr. Knaggs in Ent. Mo. Mag., vol. iii. p. 238, and p. 256. Some observations onE. Punctariawere communicated to the Entomological Society of London by Professor Westwood in 1877, on the authority of Mr. B. G. Cole. See Proc. Ent. Soc. 1877, pp. vi, vii. R.M.]7[In 1860 Andrew Murray directed attention to the disguising colours of species which, like the Alpine hare, stoat, and ptarmigan, undergo seasonal variation of colour. See a paper “On the Disguises of Nature, being an inquiry into the laws which regulate external form and colour in plants and animals.” Edinb. New Phil. Journ., Jan. 1860. In 1873 I attempted to show that these and other cases of “variable protective colouring” could be fairly attributed to natural selection. See Proc. Zoo. Soc., Feb. 4th, 1873, pp. 153–162. R.M.]8[A phenomenon somewhat analogous to seasonal change of protecting colour does occur in some Lepidoptera, only the change, instead of occurring in the same individual, is displayed by the successive individuals of the same brood. See Dr. Wallace onBombyx Cynthia, Trans. Ent. Soc. Vol. v. p. 485. R.M.]9“Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872, pp. 55–62.10[Mr. A. R. Wallace maintains that the obscurely coloured females of those butterflies which possess brightly coloured males have been rendered inconspicuous by natural selection, owing to the greater need of protection by the former sex. See “Contributions to the Theory of Natural Selection,” London, 1870, pp. 112–114. It is now generally admitted that the underside of butterflies has undergone protectional adaptation; and many cases of local variation in the colour of the underside of the wings, in accordance with the nature of the soil, &c., are known. See, for instance, Mr. D. G. Rutherford on the colour-varieties ofAterica Meleagris(Proc. Ent. Soc. 1878, p. xlii.), and Mr. J. Jenner Weir on a similar phenomenon inHipparchia Semele(loc. cit.p. xlix.) R.M.]11[The fact that moths which, like the Geometræ, rest by day with the wings spread out, are protectively marked on theupperside, fully corroborates this statement. R.M.]12“Über die Einwirkung verschiedener, während der Entwicklungsperioden angewendeter Wärmegrade auf die Färbung und Zeichnung der Schmetterlinge.” A communication to the Society of Natural Science of Steiermark, 1864.13See Exp. 9,Appendix I.14See Exp. 11,Appendix I.15See Exps. 4, 9, and 11,Appendix I.16It seems to me very necessary to have a word expressing whether a species produces one, two, or more generations in the year, and I have therefore coined the expressionmono-,di-, andpolygoneuticfromγονεύω, I produce.17[Eng. ed. In the German edition, which appeared in 1874, I was not able to support this hypothesis by geographical data, and could then only ask the question “whether in the most northern portion of its area of distribution, appears in two or only in one generation?” This question is now answered by the Swedish Expedition to the Yenisei in 1876. Herr Philipp Trybom, one of the members of this expedition, observedA. Levanaat the end of June and beginning of July, in the middle of Yenisei, in 60°-63° N. (Dagfjärilar från Yenisei in Översigt ap k. Vertensk. Akad. Förhandlingon, 1877, No. 6.) Trybom foundLevanaat Yenisk on June 23rd, at Worogova (61° 5´) on July 3rd, at Asinova (61° 25´) on July 4th, at Insarowa (62° 5´) on July 7th, and at Alinskaja (63° 25´) on July 9th. The butterflies were especially abundant at the beginning of June, and were all of the typicalLevanaform. Trybom expressly states, “we did not find a single specimen which differed perceptibly from Weismann’sFigs. 1 and 2(‘Saison-Dimorphismus’ Taf. I.).”The Swedish expedition soon left the Yenisei, and consequently was not able to decide by observations whether a second generation possessing theProrsaform appeared later in the summer. Nevertheless, it may be stated with great probability that this is not the case. The districts in whichLevanaoccurs on the Yenisei have about the same isotherm as Archangel or Haparanda, and therefore the same summer temperature. Dr. Staudinger, whose views I solicited, writes to me:—“In Finnmark (about 67° N.) I observed no species with two generations; evenPolyommatus Phlæas, which occurs there, and which in Germany has always two, and in the south, perhaps, three generations, in Finnmark has only one generation. A second generation would be impossible, and this would also be the case withLevanain the middle of Yenisei. I certainly haveLevanaandProrsafrom the middle of Amur, butLevanaflies there at the end of May, and the summers are very warm.” The middle of Amur lies, moreover, in 50° N. lat., and therefore 10°-13° south of the districts of the Yenisei mentioned.It must thus be certainly admitted that on the YeniseiA. Levanaoccurs only in theLevanaform, and that consequently this species is at the present time, in the northernmost portion of its area of distribution, in the same condition as that in which I conceive it to have been in mid Europe during the glacial period. It would be of the greatest interest to make experiments in breeding with this single-broodedLevanafrom the Yenisei, i.e., to attempt to change its offspring into theProrsaform by the action of a high temperature. If this could not be accomplished it would furnish a confirmation of my hypothesis than which nothing more rigorous could be desired.]18See Exp. 10,Appendix I.19When Dorfmeister remarks that hibernating pupæ which, at an early stage “were taken for development into a room, or not exposed to any cold, gave dwarfed, weakly and crippled,” or otherwise damaged butterflies, this is entirely attributable to the fact that this able entomologist had neglected to supply the necessary moisture to the warm air. By keeping pupæ over water I have always obtained very fine butterflies.20[For other remarkable cases of sexual dimorphism (notantigenyin the sense used by Mr. S. H. Scudder, Proc. Amer. Acad., vol. xii. 1877, pp. 150–158) see Wallace “On the Phenomena of Variation and Geographical Distribution, as illustrated by the Papilionidæ of the Malayan Region,” Trans. Linn. Soc., vol. xxv. 1865, pp. 5–10. R.M.]21[Eng. ed. Dimorphism of this kind has since been made known: the North AmericanLimenitis ArtemisandL. Proserpinaare not two species, as was formerly believed, but only one. Edwards bred both forms from eggs ofProserpina. Both are single-brooded, and both have males and females. The two forms fly together, butL. Artemisis much more widely distributed, and more abundant thanL. Proserpina. See “Butterflies of North America,” vol. ii.]22[Eng. ed. Edwards has since proved experimentally that by the application of ice a large proportion of the pupæ do indeed give rise to the var.Telamonides. He bred from eggs ofTelamonides122 pupæ, which, under natural conditions, would nearly all have given the var.Marcellus. After two months’ exposure to the low temperature there emerged from August 24th to October 16th, fifty butterflies, viz. twenty-twoTelamonides, one intermediate form betweenTelamonidesandWalshii, eight intermediate forms betweenTelamonidesandMarcellusmore nearly related to the former, six intermediate forms betweenTelamonidesandMarcellus, but more closely resembling the latter, and thirteenMarcellus. Through various mishaps the action of the ice was not complete and equal. See the “Canadian Entomologist,” 1875, p. 228. In the newly discovered case ofPhyciodes Tharosalso, Edwards has succeeded in causing the brood from the winter form to revert, by the application of ice to this same form. SeeAppendix II. for arésuméof Edwards’ experiments upon bothPapilio AjaxandPhyciodes Tharos. R.M.]23Thus from eggs ofWalshii, laid on April 10th, Edwards obtained, after a pupal period of fourteen days, from the 1st to the 6th of June, fifty-eight butterflies of the formMarcellus, one ofWalshii, and one ofTelamonides.24[The word ‘Amixie,’ from the Greekἀμιξία, was first adopted by the author to express the idea of the prevention of crossing by isolation in his essay “Über den Einfluss der Isolirung auf die Artbildung,” Leipzig, 1872, p. 49. R.M.]25[Eng. ed. In 1844, Boisduval maintained this relationship of the two forms. See Speyer’s “Geographische Verbreit. d. Schmetterl.,” i. p. 455.]26According to a written communication from Dr. Staudinger, the femaleBryoniæfrom Lapland are never so dusky as is commonly the case in the Alps, but they often have, on the other hand, a yellow instead of a white ground-colour. In the Alps, yellow specimens are not uncommon, and in the Jura are even the rule.27[According to W. F. Kirby (Syn. Cat. Diurn. Lepidop.), the species is almost cosmopolitan, occurring, as well as throughout Europe, in Northern India (var.Timeus), Shanghai (var.Chinensis), Abyssinia (var.Pseudophlæas), Massachusetts (var.Americana), and California (var.Hypophlæas). In a long series from Northern India, in my own collection, all the specimens are extremely dark, the males being almost black. R.M.]28[Eng. ed. From a written communication from Dr. Speyer, it appears that also in Germany there is a small difference between the two generations. The German summer brood has likewise more black on the upper side, although seldom so much as the South European summer brood.]29[Assuming that in all butterflies similar colours are produced by the same chemical compounds. R.M.]30[Mr. H. W. Bates mentions instances of local variation in colour affecting many distinct species in the same district in his memoir “On the Lepidoptera of the Amazon Valley;” Trans. Linn. Soc., vol. xxiii. Mr. A. R. Wallace also has brought together a large number of cases of variation in colour according to distribution, in his address to the biological section of the British Association at Glasgow in 1876. See “Brit. Assoc. Report,” 1876, pp. 100–110. For observations on the change of colour in British Lepidoptera according to distribution see papers by Mr. E. Birchall in “Ent. Mo. Mag.,” Nov., 1876, and by Dr. F. Buchanan White, “Ent. Mo. Mag.,” Dec., 1876. The colour variations in all these cases are of course notprotectiveas in the well-known case ofGnophos obscurata, &c. R.M.]31See Figs. 10 and 14, 11 and 15,Plate I.32“On the Origin and Metamorphoses of Insects,” London, 1874.33I at first thought of designating the two forms of cyclical or homochronic heredity as ontogenetic- and phyletic-cyclical heredity. The former would certainly be correct; the latter would be also applicable to alternation of generation (in which actually two or more phyletic stages alternate with each other) but not to all those cases which I attribute to heterogenesis, in which, as with seasonal dimorphism, a series of generations ofthe samephyletic stage constitute the point of departure.34When Meyer-Dürr, who is otherwise very accurate, states in his “Verzeichniss der Schmetterlinge der Schweiz,” (1852, p. 207), that the winter and summer generations ofP. Ægeriadiffer to a small extent in the contour of the wings and in marking, he has committed an error. The characters which this author attributes to the summer form are much more applicable to the female sex. There exists in this species a trifling sexual dimorphism, but no seasonal dimorphism.35P. C. Zeller, “Bemerkungen über die auf einer Reise nach Italien und Sicilien gesammelten Schmetterlingsarten.” Isis, 1847, ii.-xii.36“Isoporien der europäischen Tagfalter.” Stuttgart, 1873.37[Trans. Linn. Soc., vol. xxv. 1865, p. 9. R.M.]38It is certainly preferable to make use of the expression “metagenesis” in this special sense instead of introducing a new one. As a general designation, comprehending metagenesis and heterogenesis, there will then remain the expression “alternation of generation,” if one does not prefer to say “cyclical propagation.” The latter may be well used in contradistinction to “metamorphosis.”39Loc. cit.chap. iv.40The idea that alternation of generation is derived from polymorphism (not the reverse, as usually happens; i.e. polymorphism from alternation of generation) is not new, as I find whilst correcting the final proof. Semper has already expressed it at the conclusion of his interesting memoir, “Über Generationswechsel bei Steinkorallen,” &c. See “Zeitschrift f. wiss. Zool.” vol. xxii. 1872.41See my essay “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.42[In the case of monogoneutic species which, by artificial ‘forcing,’ have been made to give two generations in the year, it has generally been found that the reproductive system has been imperfectly developed in the second brood. A minute anatomical investigation of the sexual organs in the two broods of seasonally dimorphic insects would be of great interest, and might lead to important results. R.M.]43“Grundzüge der Zoologie.” 2nd ed. Leipzig, 1872. Introduction.44With reference to this subject, see the discussion by the Belgian Entomological Society, Brussels, 1873.45P. E. Müller, “Bidrag til Cladocerners Fortplantingshistorie,” 1868.46Sars, in “Förhandlinger i Videnskabs Selskabet i Christiania,” 1873, part i.47[Eng. ed. Recent researches on alternation of generation in the Daphniacea have convinced me thatdirectaction of external conditions does not in these cases come into consideration, but onlyindirectaction.]48See my memoir, “Über Bau und Lebenserscheinungen derLeptodora hyalina,” Zeitschrift f. wiss. Zool., vol. xxiv. part 3, 1874.49Stettin. entom. Zeit., vol. xviii. p. 83, 1857.50Compt. Rend., vol. lxxvii. p. 1164, 1873.51[“Accidental” in the sense of our being in ignorance of the laws of variation, as so frequently insisted upon by Darwin. R.M.]52[Eng. ed. Since this was written I have studied the ornamental colours of theDaphniidæ; and, as a result, I no longer doubt that sexual selection plays a very important part in the marking and colouring of butterflies. I by no means exclude both transforming factors, however; it is quite conceivable, on the contrary, that a change produced directly by climate may be still further increased by sexual selection. The above given case ofPolyommatus Phlæasmay perhaps be explained in this manner. That sexual selection plays a part in butterflies, is proved above all by the odoriferous scales and tufts of the males discovered by Fritz Müller.] [For remarks on the odours emitted by butterflies and moths, see Fritz Müller in “Jena. Zeit. f. Naturwissen.,” vol. xi. p. 99; also “Notes on Brazilian Entomology,” Trans. Ent. Soc. 1878, p. 211. The odoriferous organs of the femaleHeliconinæare fully described in a paper in “Zeit. f. Wissen. Zool.,” vol. xxx. p. 167. The position of the scent-tufts in the sphinx-moths is shown in Proc. Entom. Soc. 1878, p. ii. Many British moths, such asPhlogophora meticulosa,Cosmia trapezina, &c. &c., have tufts in a similar position. The fans on the feet ofAcidalia bisetata,Herminia barbalis,H. tarsipennalis, &c., are also probably scent organs. A large moth from Jamaica, well known to possess a powerful odour when alive (Erebus odorusLinn.), has great scent-tufts on the hind legs. For the application of the theory of sexual selection to butterflies, see, in addition, to Darwin’s “Descent of Man,” Fritz Müller in “Kosmos,” vol. ii. p. 42; also for January, 1879, p. 285; and Darwin in “Nature,” vol. xxi. January 8th, 1880, p. 237. R.M.]53Nägeli, “Entstehung und Begriff der naturhistorischen Art,” Munich, 1865, p. 25. The author interprets the facts above quoted in a quite opposite sense, but this is obviously erroneous.54See my essay, “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.55[Eng. ed. In the summer of 1877, Dr. Hilgendorf again investigated the Steinheim fossil shells, and found his former statements to be completely confirmed. At the meeting of the German Naturalists and Physicists at Munich, in 1877, he exhibited numerous preparations, which left no doubt that the chief results of his first research were correct, and that there have been deposited a series of successively derived species together with their connecting intermediate forms.]56See my essay, “Über die Berechtigung der Darwin’schen Theorie.” Leipzig, 1868.57I expressly insist upon this here, because the notice of Askenasy’s thoughtful essay which I gave in the “Archiv für Anthropologie” (1873) has frequently been misunderstood.58The experiments uponPapilio AjaxandPhyciodes Tharos, described in this Appendix, were made by Mr. W. H. Edwards (see his “Butterflies of North America;” also the “Canadian Entomologist,” vol. vii. p. 228–240, and vol. ix. p. 1–10, 51–5, and 203–6); and I have added them, together with some hitherto unpublished results, to Dr. Weismann’s Essay, in order to complete the history of the subject of seasonal dimorphism up to the present time.—R.M.59This is a striking illustration of the diversity of individual constitution so frequently insisted on by Dr. Weismann in the foregoing portion of this work.60The reader who wishes to acquire a detailed knowledge of the different varieties of this butterfly, of which a very large number are known, must consult the plates and descriptions in Edwards’ “Butterflies of North America,” vol. ii.61Mr. Edwards has shown also thatArgynnis Myrinacan lay fertile eggs when but a few hours out of the chrysalis. Canad. Ent., September, 1876, vol. viii. No. 9.62Mr. Edwards remarks that the habit of becoming lethargic is of great service to a digoneutic species in a mountain region where it is exposed to sharp changes of temperature. “If the fate of the species depended on the last larval brood of the year, and especially if the larvæ must reach a certain stage of growth before they were fitted to enter upon their hibernation, it might well happen that now and then an early frost or a tempestuous season would destroy all the larvæ of the district.”63Compare this with Weismann’s remarks, pp.19–22, and53.64See Canad. Ent., vol. ix. p. 69.65Figures of the different forms of this species are given in vol. i. of Edward’s “Butterflies of North America.”66Only the species ofSmerinthuscan be made to lay eggs regularly in confinement;Macroglossa Stellatarumlaid a number in a large gauze-covered breeding-cage; the species ofDeilephilacould not be induced to lay more than single ones in such a cage. From species ofChærocampaalso I never obtained but a few eggs, and fromSphinxandAcherontianever more than single ones.67[Eng. ed. Since the appearance of the German edition of this work, numerous descriptions of the young stages of caterpillars have been given, but in all cases without representing the relationship of the forms.] [In the excellent figures of larvæ at various stages of growth, given in some of the more recent works on Lepidoptera, there will be found much material which may be regarded as a contribution to the field of research entered on by the author in the present essay,i.e.the ontogeny and comparative morphology of larval markings, although it is much to be regretted that the figures and descriptions have not been given from this point of view. In his “Butterflies of North America,” for example, W. H. Edwards figures the young as well as the adult larvæ of species ofApatura,Argynnis,Libythea,Phyciodes,Limenitis,Colias,Papilio, &c. Burmeister, in his recently published “Lépidoptères de la République Argentine,” figures the young stages of species ofCaligo,Opsiphanes,Callidryas,Philampelus, &c. Messrs. Hellins and Buckler have figured and described the early stages of large numbers of the caterpillars of British Lepidoptera, but their figures remain unpublished. The larvæ of many of our native species belonging to the generaLiparis,Tæniocampa,Epunda,Cymatophora,Calocampa, &c., are dull when young, but become brightly coloured at the last moult. Such changes of colour are probably associated with some change, either in the habits or in the environment; and a careful study of the ontogenetic development of such species in connection with their life-history would furnish results of great value to the present inquiry. The same remarks apply to thoseNoctuælarvæ which are brightly coloured in their young stages, and become dull when adult.Among other papers which may be considered as contributions to the present subject, I may mention the following:—In 1864 Capt. Hutton published a paper, “On the Reversion and Restoration of the Silkworm, Part II.” (Trans. Ent. Soc. 1864, p. 295), in which he describes the various stages of development of several species ofBombycidæ. In 1867 G. Semper published accounts of the early stages of several Sphinx-larvæ (“Beiträge zur Entwicklungsgeschichte einiger ostasiatischer Schmetterlinge,” Verhandl. k.k. Zoolog.-botan. Gesell. in Wien, vol. xvii.). The question as to the number of claspers in youngNoctuælarvæ has been raised in notes by Dr. F. Buchanan White (“Ent. Mo. Mag.,” vol. v. p. 204) and B. Lockyer (“Entomologist,” 1871, p. 433). A valuable paper, “On the Embryonic Larvæ of Butterflies,” was published in 1871 by S. H. Scudder (“Ent. Mo. Mag.,” vol. viii. p. 122). For remarks on the development of the larva ofPapilio Merope, see J. P. Mansel Weale in Trans. Ent. Soc., 1874, p. 131, and Pl. I.; also this author on the young stages of the larva ofGynanisa Isis, Trans. Ent. Soc., 1878, p. 184. For an account of the development of the larvæ of certain North American species ofSatyrus, see W. H. Edwards in the “Canadian Entom.,” vol. xii. p. 21. Mr. P. H. Gosse’s recent description of the newly hatched caterpillar ofPapilio Homerus(Proc. Ent. Soc. 1879, p. lv), furnishes a good illustration of the value of studying the ontogeny. The natural affinities of thePapilionidæwere at one time much disputed, some systematists placing this family at the head of the Lepidoptera, and others regarding them as being more closely allied to the moths. Mr. Gosse’s observation tends to confirm the latter view, now generally received by Lepidopterists, since he states that the larva in question “suggests one of the greatSaturniadæ, such asSamia Cecropia.” Mr. Scudder, in the paper above referred to, adopts an analogous argument to show the close relationship between thePapilionidæandHesperidæ. R.M.]68[Mr. A. G. Butler has recently furnished a good illustration of the danger of classifying Lepidoptera according to the affinities of the perfect insects only, in his paper, “On the Natural Affinities of the Lepidoptera hitherto referred to the GenusAcronyctaof authors,” Trans. Ent. Soc. 1879, p. 313. If the author’s views are ultimately accepted, the species at present grouped under this genus will be distributed among theArctiidæ,Liparidæ,Notodontidæ, andNoctuæ. Mr. Butler’s determination of the affinities of the species supposed to belong to the genus mentioned, is based chiefly upon a comparative examination of the larvæ, and this is far more likely to show the true blood-relationship of the species than a comparison of the perfect insects only. A study of the comparative ontogeny can alone give a final answer to this question. R.M.]69[In his recent revision of theSphingidæ, Mr. A. G. Butler (Trans. Zoo. Soc., vol. ix. part x.) retains Walker’s arrangement. R.M.]70The deposition of black pigment may commence immediately before ecdysis.71[Mr. Herbert Goss states (Proc. Ent. Soc. 1878, p. v.) that according to his experience, the green and brown varieties ofC. Porcellus(erroneously printed asElpenorin the passage referred to) are about equally common, the former colour not being in any way confined to young larvæ. Mr. Owen Wilson in his recent work, “The Larvæ of British Lepidoptera and their food-plants,” figures (Pl. VIII., Figs. 3 and 3a) the two forms, both apparently in the adult state. During the years 1878–79, my friend, Mr. J. Evershed, jun., took five of these full-grown larvæ in Surrey, one of these being the green variety. In order to get more statistics on this subject, I applied this year (1880) to Messrs. Davis of Dartford, who informed me that among 18–20 adult caterpillars ofPorcellusin their possession, there was only one green specimen. R.M.]72I unite the generaPergesaandDarapsaof Walk. withChærocampa, Dup.; the first appears to me to be quite untenable, since it is impossible that two species, of which the caterpillars agree so completely as those ofC. ElpenorandPorcellus, can be located in different genera.Porcellusindeed was referred to the genusPergesabecause of its different contour of wings, an instance which distinctly shows how dangerous it is to attempt to found Lepidopterous genera without considering the caterpillars. The genusDarapsaalso appears to me to be of very doubtful value, and in any case requires further confirmation with respect to the larval forms.73[Mr. A. G. Butler (Trans. Zoo. Soc., vol. ix., part. x., 1876) gives a list of about eighty-four species ofChærocampa, and sixteen ofPergesa, besides numerous other species belonging to several genera placed betweenChærocampaandPergesa. OfDarapsa, he states “that this genus was founded upon most heterogeneous material, the first three species being referable to Hübner’s genusOtus, the fifth to Walker’s genusDiodosida, the sixth and eighth to the genusDaphnisof Hübner, the seventh, ninth, and tenth toChærocampaof Duponchel; there therefore remains only the fourth species, allied toChærocampa, but apparently sufficiently distinct.” The species still retained in the genusDarapsaisD. rhodocera, Wlk., from Haiti. R.M.]74[Otus Syriacusof Butler’s revision. R.M.]75Abbot and Smith. “The Natural History of the rarer Lepidopterous Insects of Georgia, collected from the observations of John Abbot, with the plants on which they feed.” London, 1797, 2 vols. fol.76[Otus ChœrilusandO. Myronof Butler’s revision. R.M.]77[To this group may also be addedAmpelophaga Rubiginosa, Ménétriés, from China and Japan, the caterpillar of which, having the distinct subdorsal line without any trace of eye-spots, is figured by Butler (loc. cit., Pl. XCI., Fig. 4). This author also gives a figure of another species belonging to the subfamilyChærocampinæ(Pl. XC., Fig. 11), viz.Acosmeryx Anceus, Cram., from Amboina, Java, Silhet, and S. India; the caterpillar is green, with seven oblique yellow stripes along the sides, and a very conspicuous white subdorsal line with a red border above. As there are no eye-spots, this species may be referred to the present group provisionally, although its general marking is very distinct from that of theChærocampagroup. R.M.]78[Eng. ed. Dr. Staudinger has since obtained the caterpillar ofC. Alectofrom Beyrout; it possesses “a very distinct subdorsal line, and on the fourth segment a beautiful eye-spot, which is repeated with gradual diminution to segments 7–8”.]79Figured in “A Catalogue of Lepidopterous Insects in the Museum of the East India Company,” by Thomas Horsfield and Frederick Moore. London, 1857. Vol. i., Pl. XI.80Figured in Trans. Ent. Soc., New Series, vol. iv., Pl. XIII.81Ibid.82[The following species figured by Butler (loc. cit.Pls. XC. and XCI.) appear to belong to the second group—Chærocampa Japonica, Boisd., which is figured in two forms, one brown, and the other green. The former has two distinct ocelli on the fourth and fifth segments, and a distinct rudiment on the sixth, whilst the subdorsal line extends from the second eye-spot to the caudal horn, and beneath this line the oblique lateral stripes stand out conspicuously in dark brown on a lighter ground. The ocelli are equally well developed on the fourth and fifth segments in the green variety, the subdorsal line commencing on the sixth segment, and extending to the caudal horn; there is no trace of a third eye-spot, nor are there any oblique lateral stripes; the insect is almost the exact counterpart ofC. Elpenorin its fourth stage. (See Fig. 21,Pl. IV.)Pergesa Mongoliana, Butl., is brown, without a trace of the subdorsal line except on the three front segments, and with only one large eye-spot on the fourth segment.Chærocampa Lewisii, Butl., from Japan, is likewise figured in two forms. The brown variety has the subdorsal line on the three front segments only, distinct ocelli on the fourth and fifth segments, and gradually diminishing rudiments on the remaining segments. The green form appears to be transitional between the present and the third group, as it possesses a distinct, but rudimentary eye-spot on the third segment, besides the fully developed ones on the fourth and fifth, and very conspicuous, but gradually decreasing repetitions of rudimentary ocelli on segments 6–10. To this group may be addedChærocampa Aristor, Boisd., the caterpillar of which is figured by Burmeister (Lép. Rép. Arg., Pl. XV., Fig. 4) in the characteristic attitude of alarm, with the front segments retracted, and the ocelli on the fourth segment prominently exposed. The subdorsal line is present in this species. Burmeister also figures two of the early stages (Pl. XV., Fig. 7, A and B), and describes the complete development ofPhilampelus Labruscæ, another species belonging to the subfamilyChærocampinæ. The earliest stage (3–4 days old) is simple green, with no trace of any marking except a black spot on each side of the fourth segment, the position of the future ocelli. A curved horn is present both in this stage and the following one, during which the caterpillar is still green, but now has seven oblique red lateral stripes. The caudal horn is shed at the second moult, after which the colour becomes darker, the adult larva (figured by Madame Mérian, in her work on Surinam, pl. 34 and Sepp., pl. 32) being mottled brown. In addition to the ocellus on the fourth segment, there is another slightly larger on the eleventh segment, so that this species may perhaps be another transition to the third group; but our knowledge is still too imperfect to attempt to generalize with safety. R.M.]

1A most minute and exact description of the newly hatched larva ofChionobas Aëllois given by the American entomologist, Samuel H. Scudder. Ann. Soc. Ent. de Belgique, xvi., 1873.

2I am aware that this certainly cannot be said of philosophers like Lotze or Herbert Spencer; but these are at the same time both naturalists and philosophers.

3“Über die Artrechte desPolyommatus AmyntasundPolysperchon.” Stett. ent. Zeit. 1849. Vol. x. p. 177–182. [In Kirby’s “Synonymic Catalogue of Diurnal Lepidoptera”Plebeius Amyntasis given as a synonym andP. Polysperchonas a var. ofP. ArgiadesPall. R.M.]

4“Die Arten der Lepidopteren-GattungInoLeach, nebst einigen Vorbemerkungen über Localvarietäten.” Stett. ent. Zeit. 1862. Vol. xxiii. p. 342.

5[Eng. ed. W. H. Edwards has since pointed out several beautiful cases of seasonal dimorphism in America. ThusPlebeius Pseudargiolusis the summer form ofP. Violacea, andPhyciodes Tharosthe summer form ofP. Marcia. See Edwards’ “Butterflies of North America,” 1868–79.]

6[Eng. ed. I learn by a written communication from Dr. Speyer that two Geometræ,Selenia TetralunariaandS. IllunariaHüb., are seasonally dimorphic. In both species the winter form is much larger and darker.] [Selenia Lunaria,S. Illustraria, and some species ofEphyra(E. PunctariaandE. Omicronaria) are likewise seasonally dimorphic. For remarks on the case ofS. Illustrariasee Dr. Knaggs in Ent. Mo. Mag., vol. iii. p. 238, and p. 256. Some observations onE. Punctariawere communicated to the Entomological Society of London by Professor Westwood in 1877, on the authority of Mr. B. G. Cole. See Proc. Ent. Soc. 1877, pp. vi, vii. R.M.]

7[In 1860 Andrew Murray directed attention to the disguising colours of species which, like the Alpine hare, stoat, and ptarmigan, undergo seasonal variation of colour. See a paper “On the Disguises of Nature, being an inquiry into the laws which regulate external form and colour in plants and animals.” Edinb. New Phil. Journ., Jan. 1860. In 1873 I attempted to show that these and other cases of “variable protective colouring” could be fairly attributed to natural selection. See Proc. Zoo. Soc., Feb. 4th, 1873, pp. 153–162. R.M.]

8[A phenomenon somewhat analogous to seasonal change of protecting colour does occur in some Lepidoptera, only the change, instead of occurring in the same individual, is displayed by the successive individuals of the same brood. See Dr. Wallace onBombyx Cynthia, Trans. Ent. Soc. Vol. v. p. 485. R.M.]

9“Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872, pp. 55–62.

10[Mr. A. R. Wallace maintains that the obscurely coloured females of those butterflies which possess brightly coloured males have been rendered inconspicuous by natural selection, owing to the greater need of protection by the former sex. See “Contributions to the Theory of Natural Selection,” London, 1870, pp. 112–114. It is now generally admitted that the underside of butterflies has undergone protectional adaptation; and many cases of local variation in the colour of the underside of the wings, in accordance with the nature of the soil, &c., are known. See, for instance, Mr. D. G. Rutherford on the colour-varieties ofAterica Meleagris(Proc. Ent. Soc. 1878, p. xlii.), and Mr. J. Jenner Weir on a similar phenomenon inHipparchia Semele(loc. cit.p. xlix.) R.M.]

11[The fact that moths which, like the Geometræ, rest by day with the wings spread out, are protectively marked on theupperside, fully corroborates this statement. R.M.]

12“Über die Einwirkung verschiedener, während der Entwicklungsperioden angewendeter Wärmegrade auf die Färbung und Zeichnung der Schmetterlinge.” A communication to the Society of Natural Science of Steiermark, 1864.

13See Exp. 9,Appendix I.

14See Exp. 11,Appendix I.

15See Exps. 4, 9, and 11,Appendix I.

16It seems to me very necessary to have a word expressing whether a species produces one, two, or more generations in the year, and I have therefore coined the expressionmono-,di-, andpolygoneuticfromγονεύω, I produce.

17[Eng. ed. In the German edition, which appeared in 1874, I was not able to support this hypothesis by geographical data, and could then only ask the question “whether in the most northern portion of its area of distribution, appears in two or only in one generation?” This question is now answered by the Swedish Expedition to the Yenisei in 1876. Herr Philipp Trybom, one of the members of this expedition, observedA. Levanaat the end of June and beginning of July, in the middle of Yenisei, in 60°-63° N. (Dagfjärilar från Yenisei in Översigt ap k. Vertensk. Akad. Förhandlingon, 1877, No. 6.) Trybom foundLevanaat Yenisk on June 23rd, at Worogova (61° 5´) on July 3rd, at Asinova (61° 25´) on July 4th, at Insarowa (62° 5´) on July 7th, and at Alinskaja (63° 25´) on July 9th. The butterflies were especially abundant at the beginning of June, and were all of the typicalLevanaform. Trybom expressly states, “we did not find a single specimen which differed perceptibly from Weismann’sFigs. 1 and 2(‘Saison-Dimorphismus’ Taf. I.).”The Swedish expedition soon left the Yenisei, and consequently was not able to decide by observations whether a second generation possessing theProrsaform appeared later in the summer. Nevertheless, it may be stated with great probability that this is not the case. The districts in whichLevanaoccurs on the Yenisei have about the same isotherm as Archangel or Haparanda, and therefore the same summer temperature. Dr. Staudinger, whose views I solicited, writes to me:—“In Finnmark (about 67° N.) I observed no species with two generations; evenPolyommatus Phlæas, which occurs there, and which in Germany has always two, and in the south, perhaps, three generations, in Finnmark has only one generation. A second generation would be impossible, and this would also be the case withLevanain the middle of Yenisei. I certainly haveLevanaandProrsafrom the middle of Amur, butLevanaflies there at the end of May, and the summers are very warm.” The middle of Amur lies, moreover, in 50° N. lat., and therefore 10°-13° south of the districts of the Yenisei mentioned.It must thus be certainly admitted that on the YeniseiA. Levanaoccurs only in theLevanaform, and that consequently this species is at the present time, in the northernmost portion of its area of distribution, in the same condition as that in which I conceive it to have been in mid Europe during the glacial period. It would be of the greatest interest to make experiments in breeding with this single-broodedLevanafrom the Yenisei, i.e., to attempt to change its offspring into theProrsaform by the action of a high temperature. If this could not be accomplished it would furnish a confirmation of my hypothesis than which nothing more rigorous could be desired.]

The Swedish expedition soon left the Yenisei, and consequently was not able to decide by observations whether a second generation possessing theProrsaform appeared later in the summer. Nevertheless, it may be stated with great probability that this is not the case. The districts in whichLevanaoccurs on the Yenisei have about the same isotherm as Archangel or Haparanda, and therefore the same summer temperature. Dr. Staudinger, whose views I solicited, writes to me:—“In Finnmark (about 67° N.) I observed no species with two generations; evenPolyommatus Phlæas, which occurs there, and which in Germany has always two, and in the south, perhaps, three generations, in Finnmark has only one generation. A second generation would be impossible, and this would also be the case withLevanain the middle of Yenisei. I certainly haveLevanaandProrsafrom the middle of Amur, butLevanaflies there at the end of May, and the summers are very warm.” The middle of Amur lies, moreover, in 50° N. lat., and therefore 10°-13° south of the districts of the Yenisei mentioned.

It must thus be certainly admitted that on the YeniseiA. Levanaoccurs only in theLevanaform, and that consequently this species is at the present time, in the northernmost portion of its area of distribution, in the same condition as that in which I conceive it to have been in mid Europe during the glacial period. It would be of the greatest interest to make experiments in breeding with this single-broodedLevanafrom the Yenisei, i.e., to attempt to change its offspring into theProrsaform by the action of a high temperature. If this could not be accomplished it would furnish a confirmation of my hypothesis than which nothing more rigorous could be desired.]

18See Exp. 10,Appendix I.

19When Dorfmeister remarks that hibernating pupæ which, at an early stage “were taken for development into a room, or not exposed to any cold, gave dwarfed, weakly and crippled,” or otherwise damaged butterflies, this is entirely attributable to the fact that this able entomologist had neglected to supply the necessary moisture to the warm air. By keeping pupæ over water I have always obtained very fine butterflies.

20[For other remarkable cases of sexual dimorphism (notantigenyin the sense used by Mr. S. H. Scudder, Proc. Amer. Acad., vol. xii. 1877, pp. 150–158) see Wallace “On the Phenomena of Variation and Geographical Distribution, as illustrated by the Papilionidæ of the Malayan Region,” Trans. Linn. Soc., vol. xxv. 1865, pp. 5–10. R.M.]

21[Eng. ed. Dimorphism of this kind has since been made known: the North AmericanLimenitis ArtemisandL. Proserpinaare not two species, as was formerly believed, but only one. Edwards bred both forms from eggs ofProserpina. Both are single-brooded, and both have males and females. The two forms fly together, butL. Artemisis much more widely distributed, and more abundant thanL. Proserpina. See “Butterflies of North America,” vol. ii.]

22[Eng. ed. Edwards has since proved experimentally that by the application of ice a large proportion of the pupæ do indeed give rise to the var.Telamonides. He bred from eggs ofTelamonides122 pupæ, which, under natural conditions, would nearly all have given the var.Marcellus. After two months’ exposure to the low temperature there emerged from August 24th to October 16th, fifty butterflies, viz. twenty-twoTelamonides, one intermediate form betweenTelamonidesandWalshii, eight intermediate forms betweenTelamonidesandMarcellusmore nearly related to the former, six intermediate forms betweenTelamonidesandMarcellus, but more closely resembling the latter, and thirteenMarcellus. Through various mishaps the action of the ice was not complete and equal. See the “Canadian Entomologist,” 1875, p. 228. In the newly discovered case ofPhyciodes Tharosalso, Edwards has succeeded in causing the brood from the winter form to revert, by the application of ice to this same form. SeeAppendix II. for arésuméof Edwards’ experiments upon bothPapilio AjaxandPhyciodes Tharos. R.M.]

23Thus from eggs ofWalshii, laid on April 10th, Edwards obtained, after a pupal period of fourteen days, from the 1st to the 6th of June, fifty-eight butterflies of the formMarcellus, one ofWalshii, and one ofTelamonides.

24[The word ‘Amixie,’ from the Greekἀμιξία, was first adopted by the author to express the idea of the prevention of crossing by isolation in his essay “Über den Einfluss der Isolirung auf die Artbildung,” Leipzig, 1872, p. 49. R.M.]

25[Eng. ed. In 1844, Boisduval maintained this relationship of the two forms. See Speyer’s “Geographische Verbreit. d. Schmetterl.,” i. p. 455.]

26According to a written communication from Dr. Staudinger, the femaleBryoniæfrom Lapland are never so dusky as is commonly the case in the Alps, but they often have, on the other hand, a yellow instead of a white ground-colour. In the Alps, yellow specimens are not uncommon, and in the Jura are even the rule.

27[According to W. F. Kirby (Syn. Cat. Diurn. Lepidop.), the species is almost cosmopolitan, occurring, as well as throughout Europe, in Northern India (var.Timeus), Shanghai (var.Chinensis), Abyssinia (var.Pseudophlæas), Massachusetts (var.Americana), and California (var.Hypophlæas). In a long series from Northern India, in my own collection, all the specimens are extremely dark, the males being almost black. R.M.]

28[Eng. ed. From a written communication from Dr. Speyer, it appears that also in Germany there is a small difference between the two generations. The German summer brood has likewise more black on the upper side, although seldom so much as the South European summer brood.]

29[Assuming that in all butterflies similar colours are produced by the same chemical compounds. R.M.]

30[Mr. H. W. Bates mentions instances of local variation in colour affecting many distinct species in the same district in his memoir “On the Lepidoptera of the Amazon Valley;” Trans. Linn. Soc., vol. xxiii. Mr. A. R. Wallace also has brought together a large number of cases of variation in colour according to distribution, in his address to the biological section of the British Association at Glasgow in 1876. See “Brit. Assoc. Report,” 1876, pp. 100–110. For observations on the change of colour in British Lepidoptera according to distribution see papers by Mr. E. Birchall in “Ent. Mo. Mag.,” Nov., 1876, and by Dr. F. Buchanan White, “Ent. Mo. Mag.,” Dec., 1876. The colour variations in all these cases are of course notprotectiveas in the well-known case ofGnophos obscurata, &c. R.M.]

31See Figs. 10 and 14, 11 and 15,Plate I.

32“On the Origin and Metamorphoses of Insects,” London, 1874.

33I at first thought of designating the two forms of cyclical or homochronic heredity as ontogenetic- and phyletic-cyclical heredity. The former would certainly be correct; the latter would be also applicable to alternation of generation (in which actually two or more phyletic stages alternate with each other) but not to all those cases which I attribute to heterogenesis, in which, as with seasonal dimorphism, a series of generations ofthe samephyletic stage constitute the point of departure.

34When Meyer-Dürr, who is otherwise very accurate, states in his “Verzeichniss der Schmetterlinge der Schweiz,” (1852, p. 207), that the winter and summer generations ofP. Ægeriadiffer to a small extent in the contour of the wings and in marking, he has committed an error. The characters which this author attributes to the summer form are much more applicable to the female sex. There exists in this species a trifling sexual dimorphism, but no seasonal dimorphism.

35P. C. Zeller, “Bemerkungen über die auf einer Reise nach Italien und Sicilien gesammelten Schmetterlingsarten.” Isis, 1847, ii.-xii.

36“Isoporien der europäischen Tagfalter.” Stuttgart, 1873.

37[Trans. Linn. Soc., vol. xxv. 1865, p. 9. R.M.]

38It is certainly preferable to make use of the expression “metagenesis” in this special sense instead of introducing a new one. As a general designation, comprehending metagenesis and heterogenesis, there will then remain the expression “alternation of generation,” if one does not prefer to say “cyclical propagation.” The latter may be well used in contradistinction to “metamorphosis.”

39Loc. cit.chap. iv.

40The idea that alternation of generation is derived from polymorphism (not the reverse, as usually happens; i.e. polymorphism from alternation of generation) is not new, as I find whilst correcting the final proof. Semper has already expressed it at the conclusion of his interesting memoir, “Über Generationswechsel bei Steinkorallen,” &c. See “Zeitschrift f. wiss. Zool.” vol. xxii. 1872.

41See my essay “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.

42[In the case of monogoneutic species which, by artificial ‘forcing,’ have been made to give two generations in the year, it has generally been found that the reproductive system has been imperfectly developed in the second brood. A minute anatomical investigation of the sexual organs in the two broods of seasonally dimorphic insects would be of great interest, and might lead to important results. R.M.]

43“Grundzüge der Zoologie.” 2nd ed. Leipzig, 1872. Introduction.

44With reference to this subject, see the discussion by the Belgian Entomological Society, Brussels, 1873.

45P. E. Müller, “Bidrag til Cladocerners Fortplantingshistorie,” 1868.

46Sars, in “Förhandlinger i Videnskabs Selskabet i Christiania,” 1873, part i.

47[Eng. ed. Recent researches on alternation of generation in the Daphniacea have convinced me thatdirectaction of external conditions does not in these cases come into consideration, but onlyindirectaction.]

48See my memoir, “Über Bau und Lebenserscheinungen derLeptodora hyalina,” Zeitschrift f. wiss. Zool., vol. xxiv. part 3, 1874.

49Stettin. entom. Zeit., vol. xviii. p. 83, 1857.

50Compt. Rend., vol. lxxvii. p. 1164, 1873.

51[“Accidental” in the sense of our being in ignorance of the laws of variation, as so frequently insisted upon by Darwin. R.M.]

52[Eng. ed. Since this was written I have studied the ornamental colours of theDaphniidæ; and, as a result, I no longer doubt that sexual selection plays a very important part in the marking and colouring of butterflies. I by no means exclude both transforming factors, however; it is quite conceivable, on the contrary, that a change produced directly by climate may be still further increased by sexual selection. The above given case ofPolyommatus Phlæasmay perhaps be explained in this manner. That sexual selection plays a part in butterflies, is proved above all by the odoriferous scales and tufts of the males discovered by Fritz Müller.] [For remarks on the odours emitted by butterflies and moths, see Fritz Müller in “Jena. Zeit. f. Naturwissen.,” vol. xi. p. 99; also “Notes on Brazilian Entomology,” Trans. Ent. Soc. 1878, p. 211. The odoriferous organs of the femaleHeliconinæare fully described in a paper in “Zeit. f. Wissen. Zool.,” vol. xxx. p. 167. The position of the scent-tufts in the sphinx-moths is shown in Proc. Entom. Soc. 1878, p. ii. Many British moths, such asPhlogophora meticulosa,Cosmia trapezina, &c. &c., have tufts in a similar position. The fans on the feet ofAcidalia bisetata,Herminia barbalis,H. tarsipennalis, &c., are also probably scent organs. A large moth from Jamaica, well known to possess a powerful odour when alive (Erebus odorusLinn.), has great scent-tufts on the hind legs. For the application of the theory of sexual selection to butterflies, see, in addition, to Darwin’s “Descent of Man,” Fritz Müller in “Kosmos,” vol. ii. p. 42; also for January, 1879, p. 285; and Darwin in “Nature,” vol. xxi. January 8th, 1880, p. 237. R.M.]

53Nägeli, “Entstehung und Begriff der naturhistorischen Art,” Munich, 1865, p. 25. The author interprets the facts above quoted in a quite opposite sense, but this is obviously erroneous.

54See my essay, “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.

55[Eng. ed. In the summer of 1877, Dr. Hilgendorf again investigated the Steinheim fossil shells, and found his former statements to be completely confirmed. At the meeting of the German Naturalists and Physicists at Munich, in 1877, he exhibited numerous preparations, which left no doubt that the chief results of his first research were correct, and that there have been deposited a series of successively derived species together with their connecting intermediate forms.]

56See my essay, “Über die Berechtigung der Darwin’schen Theorie.” Leipzig, 1868.

57I expressly insist upon this here, because the notice of Askenasy’s thoughtful essay which I gave in the “Archiv für Anthropologie” (1873) has frequently been misunderstood.

58The experiments uponPapilio AjaxandPhyciodes Tharos, described in this Appendix, were made by Mr. W. H. Edwards (see his “Butterflies of North America;” also the “Canadian Entomologist,” vol. vii. p. 228–240, and vol. ix. p. 1–10, 51–5, and 203–6); and I have added them, together with some hitherto unpublished results, to Dr. Weismann’s Essay, in order to complete the history of the subject of seasonal dimorphism up to the present time.—R.M.

59This is a striking illustration of the diversity of individual constitution so frequently insisted on by Dr. Weismann in the foregoing portion of this work.

60The reader who wishes to acquire a detailed knowledge of the different varieties of this butterfly, of which a very large number are known, must consult the plates and descriptions in Edwards’ “Butterflies of North America,” vol. ii.

61Mr. Edwards has shown also thatArgynnis Myrinacan lay fertile eggs when but a few hours out of the chrysalis. Canad. Ent., September, 1876, vol. viii. No. 9.

62Mr. Edwards remarks that the habit of becoming lethargic is of great service to a digoneutic species in a mountain region where it is exposed to sharp changes of temperature. “If the fate of the species depended on the last larval brood of the year, and especially if the larvæ must reach a certain stage of growth before they were fitted to enter upon their hibernation, it might well happen that now and then an early frost or a tempestuous season would destroy all the larvæ of the district.”

63Compare this with Weismann’s remarks, pp.19–22, and53.

64See Canad. Ent., vol. ix. p. 69.

65Figures of the different forms of this species are given in vol. i. of Edward’s “Butterflies of North America.”

66Only the species ofSmerinthuscan be made to lay eggs regularly in confinement;Macroglossa Stellatarumlaid a number in a large gauze-covered breeding-cage; the species ofDeilephilacould not be induced to lay more than single ones in such a cage. From species ofChærocampaalso I never obtained but a few eggs, and fromSphinxandAcherontianever more than single ones.

67[Eng. ed. Since the appearance of the German edition of this work, numerous descriptions of the young stages of caterpillars have been given, but in all cases without representing the relationship of the forms.] [In the excellent figures of larvæ at various stages of growth, given in some of the more recent works on Lepidoptera, there will be found much material which may be regarded as a contribution to the field of research entered on by the author in the present essay,i.e.the ontogeny and comparative morphology of larval markings, although it is much to be regretted that the figures and descriptions have not been given from this point of view. In his “Butterflies of North America,” for example, W. H. Edwards figures the young as well as the adult larvæ of species ofApatura,Argynnis,Libythea,Phyciodes,Limenitis,Colias,Papilio, &c. Burmeister, in his recently published “Lépidoptères de la République Argentine,” figures the young stages of species ofCaligo,Opsiphanes,Callidryas,Philampelus, &c. Messrs. Hellins and Buckler have figured and described the early stages of large numbers of the caterpillars of British Lepidoptera, but their figures remain unpublished. The larvæ of many of our native species belonging to the generaLiparis,Tæniocampa,Epunda,Cymatophora,Calocampa, &c., are dull when young, but become brightly coloured at the last moult. Such changes of colour are probably associated with some change, either in the habits or in the environment; and a careful study of the ontogenetic development of such species in connection with their life-history would furnish results of great value to the present inquiry. The same remarks apply to thoseNoctuælarvæ which are brightly coloured in their young stages, and become dull when adult.Among other papers which may be considered as contributions to the present subject, I may mention the following:—In 1864 Capt. Hutton published a paper, “On the Reversion and Restoration of the Silkworm, Part II.” (Trans. Ent. Soc. 1864, p. 295), in which he describes the various stages of development of several species ofBombycidæ. In 1867 G. Semper published accounts of the early stages of several Sphinx-larvæ (“Beiträge zur Entwicklungsgeschichte einiger ostasiatischer Schmetterlinge,” Verhandl. k.k. Zoolog.-botan. Gesell. in Wien, vol. xvii.). The question as to the number of claspers in youngNoctuælarvæ has been raised in notes by Dr. F. Buchanan White (“Ent. Mo. Mag.,” vol. v. p. 204) and B. Lockyer (“Entomologist,” 1871, p. 433). A valuable paper, “On the Embryonic Larvæ of Butterflies,” was published in 1871 by S. H. Scudder (“Ent. Mo. Mag.,” vol. viii. p. 122). For remarks on the development of the larva ofPapilio Merope, see J. P. Mansel Weale in Trans. Ent. Soc., 1874, p. 131, and Pl. I.; also this author on the young stages of the larva ofGynanisa Isis, Trans. Ent. Soc., 1878, p. 184. For an account of the development of the larvæ of certain North American species ofSatyrus, see W. H. Edwards in the “Canadian Entom.,” vol. xii. p. 21. Mr. P. H. Gosse’s recent description of the newly hatched caterpillar ofPapilio Homerus(Proc. Ent. Soc. 1879, p. lv), furnishes a good illustration of the value of studying the ontogeny. The natural affinities of thePapilionidæwere at one time much disputed, some systematists placing this family at the head of the Lepidoptera, and others regarding them as being more closely allied to the moths. Mr. Gosse’s observation tends to confirm the latter view, now generally received by Lepidopterists, since he states that the larva in question “suggests one of the greatSaturniadæ, such asSamia Cecropia.” Mr. Scudder, in the paper above referred to, adopts an analogous argument to show the close relationship between thePapilionidæandHesperidæ. R.M.]

Among other papers which may be considered as contributions to the present subject, I may mention the following:—In 1864 Capt. Hutton published a paper, “On the Reversion and Restoration of the Silkworm, Part II.” (Trans. Ent. Soc. 1864, p. 295), in which he describes the various stages of development of several species ofBombycidæ. In 1867 G. Semper published accounts of the early stages of several Sphinx-larvæ (“Beiträge zur Entwicklungsgeschichte einiger ostasiatischer Schmetterlinge,” Verhandl. k.k. Zoolog.-botan. Gesell. in Wien, vol. xvii.). The question as to the number of claspers in youngNoctuælarvæ has been raised in notes by Dr. F. Buchanan White (“Ent. Mo. Mag.,” vol. v. p. 204) and B. Lockyer (“Entomologist,” 1871, p. 433). A valuable paper, “On the Embryonic Larvæ of Butterflies,” was published in 1871 by S. H. Scudder (“Ent. Mo. Mag.,” vol. viii. p. 122). For remarks on the development of the larva ofPapilio Merope, see J. P. Mansel Weale in Trans. Ent. Soc., 1874, p. 131, and Pl. I.; also this author on the young stages of the larva ofGynanisa Isis, Trans. Ent. Soc., 1878, p. 184. For an account of the development of the larvæ of certain North American species ofSatyrus, see W. H. Edwards in the “Canadian Entom.,” vol. xii. p. 21. Mr. P. H. Gosse’s recent description of the newly hatched caterpillar ofPapilio Homerus(Proc. Ent. Soc. 1879, p. lv), furnishes a good illustration of the value of studying the ontogeny. The natural affinities of thePapilionidæwere at one time much disputed, some systematists placing this family at the head of the Lepidoptera, and others regarding them as being more closely allied to the moths. Mr. Gosse’s observation tends to confirm the latter view, now generally received by Lepidopterists, since he states that the larva in question “suggests one of the greatSaturniadæ, such asSamia Cecropia.” Mr. Scudder, in the paper above referred to, adopts an analogous argument to show the close relationship between thePapilionidæandHesperidæ. R.M.]

68[Mr. A. G. Butler has recently furnished a good illustration of the danger of classifying Lepidoptera according to the affinities of the perfect insects only, in his paper, “On the Natural Affinities of the Lepidoptera hitherto referred to the GenusAcronyctaof authors,” Trans. Ent. Soc. 1879, p. 313. If the author’s views are ultimately accepted, the species at present grouped under this genus will be distributed among theArctiidæ,Liparidæ,Notodontidæ, andNoctuæ. Mr. Butler’s determination of the affinities of the species supposed to belong to the genus mentioned, is based chiefly upon a comparative examination of the larvæ, and this is far more likely to show the true blood-relationship of the species than a comparison of the perfect insects only. A study of the comparative ontogeny can alone give a final answer to this question. R.M.]

69[In his recent revision of theSphingidæ, Mr. A. G. Butler (Trans. Zoo. Soc., vol. ix. part x.) retains Walker’s arrangement. R.M.]

70The deposition of black pigment may commence immediately before ecdysis.

71[Mr. Herbert Goss states (Proc. Ent. Soc. 1878, p. v.) that according to his experience, the green and brown varieties ofC. Porcellus(erroneously printed asElpenorin the passage referred to) are about equally common, the former colour not being in any way confined to young larvæ. Mr. Owen Wilson in his recent work, “The Larvæ of British Lepidoptera and their food-plants,” figures (Pl. VIII., Figs. 3 and 3a) the two forms, both apparently in the adult state. During the years 1878–79, my friend, Mr. J. Evershed, jun., took five of these full-grown larvæ in Surrey, one of these being the green variety. In order to get more statistics on this subject, I applied this year (1880) to Messrs. Davis of Dartford, who informed me that among 18–20 adult caterpillars ofPorcellusin their possession, there was only one green specimen. R.M.]

72I unite the generaPergesaandDarapsaof Walk. withChærocampa, Dup.; the first appears to me to be quite untenable, since it is impossible that two species, of which the caterpillars agree so completely as those ofC. ElpenorandPorcellus, can be located in different genera.Porcellusindeed was referred to the genusPergesabecause of its different contour of wings, an instance which distinctly shows how dangerous it is to attempt to found Lepidopterous genera without considering the caterpillars. The genusDarapsaalso appears to me to be of very doubtful value, and in any case requires further confirmation with respect to the larval forms.

73[Mr. A. G. Butler (Trans. Zoo. Soc., vol. ix., part. x., 1876) gives a list of about eighty-four species ofChærocampa, and sixteen ofPergesa, besides numerous other species belonging to several genera placed betweenChærocampaandPergesa. OfDarapsa, he states “that this genus was founded upon most heterogeneous material, the first three species being referable to Hübner’s genusOtus, the fifth to Walker’s genusDiodosida, the sixth and eighth to the genusDaphnisof Hübner, the seventh, ninth, and tenth toChærocampaof Duponchel; there therefore remains only the fourth species, allied toChærocampa, but apparently sufficiently distinct.” The species still retained in the genusDarapsaisD. rhodocera, Wlk., from Haiti. R.M.]

74[Otus Syriacusof Butler’s revision. R.M.]

75Abbot and Smith. “The Natural History of the rarer Lepidopterous Insects of Georgia, collected from the observations of John Abbot, with the plants on which they feed.” London, 1797, 2 vols. fol.

76[Otus ChœrilusandO. Myronof Butler’s revision. R.M.]

77[To this group may also be addedAmpelophaga Rubiginosa, Ménétriés, from China and Japan, the caterpillar of which, having the distinct subdorsal line without any trace of eye-spots, is figured by Butler (loc. cit., Pl. XCI., Fig. 4). This author also gives a figure of another species belonging to the subfamilyChærocampinæ(Pl. XC., Fig. 11), viz.Acosmeryx Anceus, Cram., from Amboina, Java, Silhet, and S. India; the caterpillar is green, with seven oblique yellow stripes along the sides, and a very conspicuous white subdorsal line with a red border above. As there are no eye-spots, this species may be referred to the present group provisionally, although its general marking is very distinct from that of theChærocampagroup. R.M.]

78[Eng. ed. Dr. Staudinger has since obtained the caterpillar ofC. Alectofrom Beyrout; it possesses “a very distinct subdorsal line, and on the fourth segment a beautiful eye-spot, which is repeated with gradual diminution to segments 7–8”.]

79Figured in “A Catalogue of Lepidopterous Insects in the Museum of the East India Company,” by Thomas Horsfield and Frederick Moore. London, 1857. Vol. i., Pl. XI.

80Figured in Trans. Ent. Soc., New Series, vol. iv., Pl. XIII.

81Ibid.

82[The following species figured by Butler (loc. cit.Pls. XC. and XCI.) appear to belong to the second group—Chærocampa Japonica, Boisd., which is figured in two forms, one brown, and the other green. The former has two distinct ocelli on the fourth and fifth segments, and a distinct rudiment on the sixth, whilst the subdorsal line extends from the second eye-spot to the caudal horn, and beneath this line the oblique lateral stripes stand out conspicuously in dark brown on a lighter ground. The ocelli are equally well developed on the fourth and fifth segments in the green variety, the subdorsal line commencing on the sixth segment, and extending to the caudal horn; there is no trace of a third eye-spot, nor are there any oblique lateral stripes; the insect is almost the exact counterpart ofC. Elpenorin its fourth stage. (See Fig. 21,Pl. IV.)Pergesa Mongoliana, Butl., is brown, without a trace of the subdorsal line except on the three front segments, and with only one large eye-spot on the fourth segment.Chærocampa Lewisii, Butl., from Japan, is likewise figured in two forms. The brown variety has the subdorsal line on the three front segments only, distinct ocelli on the fourth and fifth segments, and gradually diminishing rudiments on the remaining segments. The green form appears to be transitional between the present and the third group, as it possesses a distinct, but rudimentary eye-spot on the third segment, besides the fully developed ones on the fourth and fifth, and very conspicuous, but gradually decreasing repetitions of rudimentary ocelli on segments 6–10. To this group may be addedChærocampa Aristor, Boisd., the caterpillar of which is figured by Burmeister (Lép. Rép. Arg., Pl. XV., Fig. 4) in the characteristic attitude of alarm, with the front segments retracted, and the ocelli on the fourth segment prominently exposed. The subdorsal line is present in this species. Burmeister also figures two of the early stages (Pl. XV., Fig. 7, A and B), and describes the complete development ofPhilampelus Labruscæ, another species belonging to the subfamilyChærocampinæ. The earliest stage (3–4 days old) is simple green, with no trace of any marking except a black spot on each side of the fourth segment, the position of the future ocelli. A curved horn is present both in this stage and the following one, during which the caterpillar is still green, but now has seven oblique red lateral stripes. The caudal horn is shed at the second moult, after which the colour becomes darker, the adult larva (figured by Madame Mérian, in her work on Surinam, pl. 34 and Sepp., pl. 32) being mottled brown. In addition to the ocellus on the fourth segment, there is another slightly larger on the eleventh segment, so that this species may perhaps be another transition to the third group; but our knowledge is still too imperfect to attempt to generalize with safety. R.M.]

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