Chap. XI. 
BUTTERFLIES AND MOTHS. 
389 
is usual with their sex in this genus, for they are gaily 
decorated in nearly the same manner as the males, but 
in a somewhat less degree. Hence in these two species 
the bright colours of the males seem to have been trans- 
ferred to the females; whilst the male of the tenth 
species has either retained or recovered the plain 
colours of the female as v r ell as of the parent-form of 
the genus ; the two sexes being thus rendered in both 
cases, though in an opposite manner, nearly alike. In 
the allied genus Eubagis, both sexes of some of the 
species are plain-coloured and nearly alike ; whilst 
with the greater number the males are decorated with 
beautiful metallic tints, in a diversified manner, and 
differ much from their females. The females through- 
out the genus retain the same general style of colouring, 
so that they commonly resemble each other much more 
closely than they resemble their own proper males. 
In the genus Papilio, all the species of the .ZEneas 
group are remarkable for their conspicuous and strongly 
contrasted colours, and they illustrate the frequent ten- 
dency 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 a little or very much more superbly coloured than 
the females. The genus Junonia allied to our Vanessm 
offers a nearly parallel case, for although the sexes of 
most of the species resemble each other and are desti- 
tute of rich colours, yet in certain species, as in J. oenone , 
the male is rather more brightly coloured 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 Theclse, in which both sexes 
