BUTTERFLIES AND MOTHS. 317 



much in the two sexes.-" This fact is at present inexplicable; 

 but if it should hereafter be found that the formation of an ocellus 

 is due to some change in the tissues of the wings, for Instance, 

 occurring at a very early period of development, we might expect, 

 from what we know of the laws of inheritance, that it would be 

 transmitted to both sexes, though arising and perfected in one 

 sex alone. 



On the whole, though many serious objections may be urged, 

 it seems probable that most of the brilliantly colored species of 

 Lepidoptera owe their colors to sexual selection, excepting in 

 certain cases, presently to be mentioned, in which conspicuous 

 colors have been gained through mimicry as a protection. From 

 the ardor of the male throughout the animal kingdom, he is 

 generally willing to accept any female; and it is the female which 

 usually exerts a choice. Hence, if sexual selection has been 

 efficient with the Lepidoptera, the male, when the sexes differ, 

 ought to be the more brilliantly colored, and this undoubtedly is 

 the case. When both sexes are brilliantly colored and resemble 

 each other, the. characters acquired by the males appear to have 

 been transmitted to both. We are led to this conclusion by cases, 

 even within the same genus, of gradation from an extraordinary 

 amount of difference to identity in color between the two sexes. 



But it may be asked whether the differences in color between 

 the sexes may not be accounted for by other means besides 

 sexual selection. Thus the males and females of the same species 

 of butterfly are in several eases known™ to inhabit different sta- 

 tions, the former commonly basking in the sunshine, the latter 

 haunting gloomy forests. It Is therefore possible that different 

 conditions of life may have acted directly on the two sexes; but 

 this is not probable," as in the adult state they are exposed to 

 different conditions during a very short period; and the larvae 

 of both are exposed to the same conditions. Mr. Wallace be- 

 lieves that the difference between the sexes is due not so much 

 to the males having been modified, as to the females having in all 

 or almost all cases acquired dull colors for the sake of protection. 

 It seems to me, on the contrary, far more probable that it Is the 

 males which have been chiefly modified through sexual selec- 

 tion, the females having been comparatively little changed. 

 We can thus understand how It Is that the females of allied 

 species generally resemble one another so much more closely 



2s Mr. Bates was so kind as to lay this subject before the Entomo- 

 logical Society, and I have received answers to this effect from sev- 

 eral entomologists. 



28 H. W. Bates, 'The Naturalist on the Amazons,' vol. ii. 1863, p. 228. 

 A. R. Wallace, in 'Transact. Linn. Sec' vol. xxv. 1865, p. 10. 



^ On this whole subject see 'The Variation of Animals and Plants 

 under Domestication,' 1868, vol. ii. chap, xxiil. 



