BUTTERFLIES AND MOTHS. 307 



Instance in P. ascanius, the males and females are alike; in utliers 

 the males are either a little brighter, or very much more superb 

 than the females. The genus Junonia, allied to our Vanessse, 

 offers a nearly parallel case, for although the sexes of most of 

 the species resemble each other, and are destitute of rich colors, 

 yet in certain species, as in J. cenone, the male is rather more 

 bright-colored than the female, and in a few (for instance J. 

 andremiaja) the male is so different from the female that he 

 might be mistaken for an entirely distinct species. 



Another striking case was pointed out to me in the British 

 Museum by Mr. A. Butler, namely, one of the tropical American 

 Theclae, in which both sexes are nearly alike and wonderfully 

 splendid; in another species the male is colored in a similarly 

 gorgeous manner, whilst the whole upper surface of the female 

 is of a dull uniform brown. Our common little English blue 

 butterflies of the genus Lycaena illustrate the various differences 

 in color between the sexes, almost as well, though not in so 

 striking a manner, as the above exotic genera. In Lycaena 

 agestis both sexes have wings of a brown color, bordered with 

 small ocellated orange spots, and are thus alike, in L. cegon 

 the wings of the male are of a fine blue, bordered with black; 

 whilst those of the female are brown, with a similar border, 

 closely resembling the wings of L. agestis. Lastly, in L. arion 

 both sexes are of a blue color and are very like, though in the 

 female the edges of the wings are rather duskier, with the black 

 spots plainer; and in a bright blue Indian species both sexes are 

 still more alike. 



I have given the foregoing details in order to show, in the first 

 place, that when the sexes of butterflies differ, the male as a 

 general rule is the more beautiful, and departs more from the 

 usual type of coloring of the group to which the species be- 

 longs. Hence in most groups the females of the several species 

 resemble each other much more closely than do the males. In 

 some cases, however, to which I shall hereafter allude, the females 

 are colored more splendidly than the males. In the second place, 

 these details have been given to bring clearly before the mind 

 that within the same genus, the two sexes frequently present 

 every gradation from no difference in color, to so great a differ- 

 ence that it was long before the two were placed by entomologists 

 in the same genus. In the third place, we have seen that when 

 the sexes nearly resemble each other, this appears due either 

 to the male having transferred his colors to the female, or to the 

 male having retained, or perhaps recovered, the primordial col- 

 ors of the group. It also deserves notice that in those groups in 

 which the sexes differ, the females usually somewhat resemble 

 'the males, so that when the males are beautiful to an extraor- 

 dinary degree, the females almost invariably exhibit some degree 



