Studies in the Theory of Descent, Volume I

[The eye-spots on Ch. Nerii have thus been supposed by some observers to be imitations of the flowers of the periwinkle, one of its food-plants. See, for instance, Sir John Lubbock’s “Scientific Lectures,” p. 51. R.M.]

148

“On Insects and Insectivorous Birds,” Trans. Ent. Soc. 1869, p. 21.

149

Ibid., p. 27.

150

[Messrs. Weir and Butler inform me that they have not experimented with Sphinx-larvæ. R.M.]

151

[It appears that the nauseous character of these last butterflies is to a certain extent retained after death, as I found that in an old collection which had been destroyed by mites, the least mutilated specimens were species of Danais and Euplæa, genera which are known to be distasteful when living, and to serve as models for mimicry. See Proc. Ent. Soc. 1877, p. xii. R.M.]

152

[This bears out the view expressed in a previous note 129 (#cn_132), p. 290 (#Page_290), that the grotesque attitude and caudal tentacles are more for protection against ichneumons than against larger foes. R.M.]

153

These experiments, as already mentioned above, were not made with the common German lizard (Lacerta Stirpium), but with the large South European Lacerta Viridis.

154

Thus, Boisduval states of this caterpillar, which in Provence lives on Euphorbia esula and allied species: – “Its resemblance to a serpent, and its brilliant colour, permit of its being easily discovered.” This was written in 1843, long before natural selection was thought of.

155

Or some other extinct analogously-marked species.

156

[See Darwin’s remarks on the struggle for life being most severe between individuals and varieties of the same species “Origin of Species,” 6th ed. p. 59. R.M.]

157

[Compare this with Darwin’s remarks on “analogous variations,” “Origin of Species,” 6th ed., p. 125. R.M.]

158

“Zoologische Studien auf Capri. II. Lacerta muralis cærula, ein Beitrag zur Darwin’schen Lehre.” Leipzig, 1874. [The subject of colour-variation in lizards has been much discussed in “Nature” since the publication of the above mentioned essay; see vol. xix., pp. 4, 53, 97, and 122, and vol. xx., pp. 290 and 480. R M.]

159

“Über die Berechtigung der Darwin’schen Theorie.” Leipzig, 1868. See also the previous essay “On the Seasonal Dimorphism of Butterflies,” pp. 112–116 (#Page_112).

160

[Mr. A. G. Butler has recently advanced the view that this family is not allied to the Sphingidæ, but is related on the one side to the Pyrales, and on the other to the Gelechiidæ. See his paper “On the Natural Affinities of the Lepidopterous Family Ægeriidæ,” Trans. Ent. Soc. 1878, p. 121. R.M.]

161

I am indebted to my esteemed colleague, Prof. Gestäcker, for the knowledge of this specimen.

162

Cat. Lep. East India Co., Pl. VIII.

163

Such a residue is distinctly visible in S. Ocellatus: see Fig. 70, Pl. VII.

164

[The question here also suggests itself as to why the dorsal line should not have been the primary longitudinal stripe, seeing that such a marking is almost naturally produced in many caterpillars by the food in the alimentary canal; or, in other words, why has not natural selection taken advantage of such an obvious means of producing a stripe in cases where it would have been advantageous? In answer to this I may state, that in large numbers of species the dorsal line has thus become utilized; but in the case of large caterpillars resting among foliage, it can be easily seen that light lateral (i. e. subdorsal) stripes, are more effective in breaking the homogeneity of the body than a dorsal line only slightly darker than the general ground-colour. Lateral lines are in fact visible from two directions of space. If a caterpillar thus marked be placed on a twig, these lines are visible when we look at the creature’s back or at either side. That the subdorsal are therefore the primary lines, as shown by Dr. Weismann’s observations of the ontogeny of many of the Sphingidæ, is quite in harmony with the view of their having been produced by natural selection. R.M.]

165

“Die Darwin’sche Theorie. Elf Vorlesungen über die Entstehung der Thiere und Pflanzen durch Naturzüchtung.” 2nd ed., Leipzig, 1875, p. 195.

166

[In the following species, already mentioned in previous notes, the oblique stripes are bounded at their upper extremities by a conspicuous subdorsal line: —Acosmeryx Anceus, Cram.; Sphinx Cingulata, Fabr.; Pachylia Ficus, Linn.; P. Syces, Hübn. In Pseudosphinx Cyrtolophia, Butl., the oblique white stripes, beautifully shaded with pink, run into the white pink-bordered dorsal line, so that when seen from above the markings present the appearance of the midrib and lateral veins of a leaf, and are probably specially adapted for this purpose. R.M.]

167

[The dorsal line as well as the oblique stripes is present in the caterpillar of Smerinthus Tartarinovii, Ménét.; and in Ambulyx Gannascus, Stoll., the oblique stripes are bounded above by a subdorsal line, as in the species named in the preceding note. R.M.]

168

Cat. Lep. East India Co., Pl. XI.

169

[Compare this with Darwin’s “Origin of Species” (1st. ed. p. 440), where it is stated that when an animal, during any part of its embryonic career, is active, and has to provide for itself, “the period of activity may come on earlier or later in life; but whenever it comes on, the adaptation of the larva to its conditions of life is just as perfect and beautiful as in the adult animal. From such special adaptations the similarity of the larvæ or active embryos of allied animals is sometimes much obscured.” R.M.]

170

[For Fritz Müller’s application of this principle to the case of certain groups of Brazilian butterflies see Appendix II (#P1_A2). to this Part. R.M.]