But the shape of the wings is not the only sexual difference. The colours of the male are always darker than those of the female, and the markings on a much smaller scale. Nay, some of the markings found in the one entirely disappear in the other. Thus the female of H. atlas has a small supplemental vitreous spot on the disk of the wings;[1] in many of the smaller species the form of the vitreous spaces is quite different in the two sexes; and there is commonly some additional bar or spots peculiar to the female. In short, when an attempt is made to unite the sexes to their legitimate partners, it must be kept in mind that this relationship has often no other external indication than an approximation in size, and a certain general resemblance in the design and colour of the wings.
In consequence of these considerations having been overlooked, there is reason to believe that the two sexes have sometimes been described as distinct species. Cramer committed this error in regard to A. erythrinæ, and it is not surprising that he should have done so, for they are remarkably dissimilar. A fine species from Assam has recently been described by the Rev. F. W. Hope, under the name of Bombyx spectabilis, and figured with his
- ↑ We are informed by Mr. Westwood that there is an article on the habits and variations of the sex of H. atlas in the "Actes de la Sociéte Linnéenne de Bourdeanx, t. iv. 3d levraison. June 1830:" a work which we have not had an opportunity of consulting.
