Note 67 — Part II. ON THE FINAL CAUSES OF TRANSFORMATION.

[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 of Apatura, Argynnis, Libythea, Phyciodes, Limenitis, Colias, Papilio, &c. Burmeister, in his recently published “Lépidoptères de la République Argentine,” figures the young stages of species of Caligo, 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and described the early stages of large numbers of the caterpillars of British Lepidoptera, but their figures remain unpublished.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 genera Liparis, 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 those Noctuæ larvæ 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 of Bombycidæ. 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 young Noctuæ larvæ 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 of Papilio 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 of Gynanisa Isis, Trans. Ent. Soc., 1878, p. 184. For an account of the development of the larvæ of certain North American species of Satyrus, see W. H. Edwards in the “Canadian Entom.,” vol. xii. p. 21. Mr. P. H. Gosse’s recent description of the newly hatched caterpillar of Papilio Homerus (Proc. Ent. Soc. 1879, p. lv), furnishes a good illustration of the value of studying the ontogeny. The natural affinities of the Papilionidæ were 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 great Saturniadæ, such as Samia Cecropia.” Mr. Scudder, in the paper above referred to, adopts an analogous argument to show the close relationship between the Papilionidæ and Hesperidæ. R.M.]