only make this assumption for the sake of simplicity, and not because I am convinced that the existing
Rhopalocera are actually the oldest Lepidopterous group.
27
Zeitschrift für wissenschaftl. Zoologie, vol. xx. p. 519.
28
[See for instance Lubbock’s “Origin and Metamorphoses of Insects,” chap. iii.; and F. M. Balfour’s “Comparative Embryology,” vol. i., 1880, pp. 327 – 356. This last work contains an admirable résumé of our knowledge of the embryonic development of insects up to the date of publication. R.M.]
29
Are not the 4th, 11th, and 12th segments destitute of the rudiments of legs as in the larvæ of all existing saw-flies? I might almost infer this from Bütschli’s figures (see for instance Pl. XXV., Fig. 17A).
30
[The grub-formed Hymenopterous larvæ, like the larvæ of all other holometabolous insects, thus represent an acquired degenerative stage in the development, i. e. an adaptation to the conditions of life at that stage. Bearing in mind the above-quoted observations of Bütschli and the caterpillar-like form of the Terebrantiate group of Hymenopterous larvæ, the following remarks of Balfour’s (loc. cit. p. 353), appear highly suggestive: – “While in a general way it is clear that the larval forms of insects cannot be expected to throw much light on the nature of insect ancestors, it does nevertheless appear to me probable that such forms as the caterpillars of the Lepidoptera are not without a meaning in this respect. It is easy to conceive that even a secondary larval form may have been produced by the prolongation of one of the embryonic stages; and the general similarity of a caterpillar to Peripatus, and the retention by it of post-thoracic appendages, are facts which appear to favour this view of the origin of the caterpillar form.” See also Sir John Lubbock, loc. cit., pp. 93 and 95. R.M.]
