BUTTERFLIES AND MOTHS. 319 



instance, of the comfiaon brimstone butterfly (Gonepteryx), is of 

 a far more intense yellow than the female, though she is equally 

 conspicuous; and it does not seem probable that she specially 

 acquired her pale tints as a protection, though it is probable 

 that the male acquired his bright colors as a sexual attraction. 

 The female of Anthocharis cardamines does not possess the 

 beautiful orange wing-tips of the male; consequently she closely 

 resembles the white butterflies (Pieris) so common in our gar- 

 dens; but we have no evidence that this resemblance is bene- 

 ficial to her. As, on the other hand, she resembles both sexes 

 of several other species of the genus inhabiting various quarters 

 of the world, it is probable that she has simply retained to a 

 large extent her primordial colors. 



Finally, as we have aeen, various considerations lead to the 

 conclusion that with the greater number of brilliantly-colored 

 Lepidoptera it is the male which has been chiefly modified 

 through sexual selection; the amount of difference between the 

 sexes mostly depending on the form of inheritance which has 

 prevailed. Inheritance is governed by so many unknown laws 

 or conditions, that it seems to us to act in a capricious manner;'' 

 and we can thus, to a certain extent, understand how it is that 

 with closely allied species the sexes either differ to an astonish- 

 ing degree, or are identical in color. As all the successive steps 

 in the process of variation are necessarily transmitted through 

 the female, a greater or less number of such steps might readily 

 become developed in her; and thus we can understand the fre- 

 quent gradations from an extreme difference to none at all be- 

 tween the sexes of allied species. These cases of gradation, it 

 may be added, are much too common to favor the supposition 

 that we here see females actually undergoing the process of 

 transition and losing their brightness for the sake of protection; 

 for we have every reason lo conclude that at any one time the 

 greater number of species are in a fixed condition. 



Mimicry. — This principle was first made clear in an admir- 

 able paper by Mr. Bates,-" who thus threw a flood of light on 

 many obscure problems. It had previously been observed that 

 certain butterflies in S. America belonging to quite distinct fam- 

 ilies, resembled the Heliconidae so closely in every stripe and 

 shade of color, that they could not be distinguished save by an 

 experienced entomologist. As the HeliconidK are colored in 

 their usual manner, whilst the others depart from the usual color- 

 ing of the groups to which they belong, it is clear that the latter 



^ 'The Variation of Animals and Plants under Domestication,' vol. 

 ii. chap. xii. p. 17. 

 '^ 'Transact. Linn. Soc' vol. xxiii. 1862, p. 495. 



