Generic Character.—See Pl. 15.
- A. mas. Alis anticis falcato-acuminatis, fuscis, fasciâ mediâ margineque postico flavo; posticis infra flavescentibus colore griseo variis, basi maculis 4 fulvis.
- Fem. Alis infra albentibus colore griseo variis; anticis integris, supra fuscis, fasciâ mediâ margineque postico albentibus; posticarum basi maculis 4 fulvis.
- Male. Anterior wings angulated, brown, with a central band and hind margin yellow; posterior beneath yellowish marbled with grey, base with 4 fulvous spots.
- Female. Anterior wings entire, above brown, with a central band and hind margin whitish; all the wings beneath whitish marbled with grey; base of the posterior with 4 fulvous spots.
- Pieris Crisia. Godart. En. Méth. p. 197. Male. Drury, v. 3. pl. 37. f. 1. 2?
The extraordinary difference existing between the sexes of exotic Lepidoptera, and particularly among the Butterflies, (Papilionidæ Lin.) is a subject which hitherto has received but little attention; nor am I aware of any entomological writer who has described those characters which absolutely distinguish the sexes: characters which, I am persuaded, will hereafter be found of the first importance in a natural arrangement of these insects. But in the prosecution of this desirable object, the naturalist, as far as regards foreign Lepidoptera, will have to encounter serious obstacles; many individuals must be examined of each species, and some of these dissected. It falls to the lot of few to pursue their inquiries in the native regions of these insects. Collections in this country are very few, and some of these are not always open to the scientific labourer; neither can specimens be sacrificed for dissection, where there are not more than two or three individuals of a species.
This is in general a very rare insect; observed for the first time by Dr. Langsdorff and myself early in June (the tropical autumn), in a wood adjoining the Organ Mountains at Rio de Janeiro. From its local abundance, we were able to ascertain the sexes. The two upper figures are of the female, and the lower of the male insect.