[31] Trans. of the Ent. Soc. of London, ii. pp. 59, 62.
[32] Considering that the true Vanessa Atalanta, of more northern latitudes, does occasionally occur around Funchal, it may be reasonably contended that the fact of its coexistence (on the same spot) with the V. Callirhoë is strong presumptive proof that the latter is a true species, and no climatal or insular modification of the former. And so, judging from a distance, and without local evidence to explain this phænomenon, I should have concluded myself: nevertheless, recollecting how easy of transport the larvæ and pupæ of Lepidoptera necessarily are (of which we have the plainest assurance in the almost certain introduction of the Pontia Brassicæ, Sphinx Convolvuli, Acherontia Atropos, &c. into those islands), especially in a region which for more than a century has been receiving a constant supply of vegetables and ornamental plants from western Europe; I am induced to believe that the appearance of the Atalanta is a comparatively recent one, whilst that of the Callirhoë (which, unlike the typical Red Admiral, has naturalized itself in nearly all portions of the group) must be referred to the remote period when migrations over a long-lost continuous land were in regular operation. The slowness of the change, in external aspect, which the isolation of insects from geological causes would seem to bring about (and which follows, as a corollary, if the above conclusion be true), I propose to discuss in a subsequent chapter of this work.
[33] Insecta Maderensia, p. 260.
[34] Insecta Maderensia, pp. 268, 269.
[35] Religion of Nature Delineated, p. 99.
[36] Although the result of a primary (or creative) adjustment to special circumstances, rather than of a secondary adaptation, brought about by a self-modifying capability; we may just call attention to the fact, that most of the blind insects, whether associates within the nests of ants, or natives of subterranean caverns, have either their palpi or antennæ anomalously developed,—as though, partially (although how, and in what degree, we cannot possibly ascertain), to make amends for the inconvenience which a total want of sight must, necessarily entail.
[37] This is certainly rendered probable, however, from the fact that a large proportion of these apterous species are members of genera which are usually winged,—such as Tarus, Loricera, Calathus, Olisthopus, Argutor, Trechus, Hydrobius, Ephistemus, Syncalypta, Phlœophagus, Tychius, Longitarsus, Chrysomela, Scymnus, Corylophus, Helops, and Othius,—whilst the knowledge that, out of twenty-nine genera which I believe to be endemic in those islands, six only are winged (the remaining twenty-three being apterous), will not tend to diminish the probability that there is something peculiar in the action of Madeiran influences generally on the alary system of the insect tribes.
[38] I do not think it necessary to apologize for the apparent disposal of this quæstio vexata; because, from the wildness of the upland ridges to which the D. obscuroguttatus is in Madeira exclusively confined, I deem it an absolute impossibility that it could ever have been introduced, through any chance agencies whatsoever. And hence, unless we reject the doctrine of specific centres in toto, I contend that it must have migrated, together with other insects similarly circumstanced, by ordinary means, and without natural impediments, from its own area of diffusion.
[39] I am informed by Dr. Hooker, that the only two insects (belonging respectively to the orders Coleoptera and Lepidoptera) which he detected in Kerguelen's Land were wingless.
[40] Insecta Maderensia, p. 6.