INSECTS. 351 



males, but in a somewhat less degree. Hence in these two 

 latter species the bright colors of the males seem to have 

 been transferred to the females; while in the tenth species 

 the male has either retained or recovered the plain colors of 

 the female, as well as of the parent-form of the genus. The 

 sexes in these three cases have thus been rendered nearly 

 alike, though in an opposite manner. In the allied genus 

 Eubagis, both sexes of some of the species are plain-colored 

 and nearly alike; while the greater number of the males are 

 decorated with beautiful metallic tints in a diversified 

 manner, and differ much from their females. The females 

 throughout the genus retain the same general style of 

 coloring, so that they resemble one another much more 

 closely than they resemble their own males. 



In the genus Papilio all the species of the ^Eneas group 

 are remarkable for their conspicuous and strongly con- 

 trasted colors, and they illustrate the frequent tendency to 

 gradation in the amount of difference between the sexes. 

 In a few species, for instance in P. ascanius, the males and 

 females are alike; in others the males are either a little 

 brighter, or very much more superb than the females. The 

 genus Junonia, allied to our Vanessa?, 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 /. 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 Brit- 

 ish 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, while 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 Lyccena agestis both sexes have 

 wings of a brown color, bordered with small ocellated 

 orange spots and are thus alike. In L. ORgon the wings of 

 the male are of a fine blue bordered with black, while 

 those of the female are brown with a similar border closely 



