1 8 MY LIFE [Chap 



because he is the most beautiful, is an inference supported by 

 singularly little evidence. The first kind of sexual selection 

 I hold as strongly and as thoroughly as Darwin himself; the 

 latter I at first accepted, following Darwin's conclusions 

 from what appeared to be strong evidence explicable 

 in no other way ; but I soon came to doubt the possibility 

 of such an explanation, at first from considering the fact that 

 in butterflies sexual differences are as strongly marked as in 

 birds, and it was to me impossible to accept female choice in 

 their case, while, as the whole question of colour came to be 

 better understood, I saw equally valid reasons for its total 

 rejection even in birds and mammalia. 



But here my view really extends the influence of natural 

 selection, because I show in how many unsuspected ways 

 colour and marking is of use to its possessor. I first stated 

 my objections to " female choice " in my review of the 

 " Descent of Man " (1871), and more fully developed it in my 

 "Tropical Nature" (1878), while in my " Darwinism " (1889), 

 I again discussed the whole subject, giving the results of more 

 mature consideration. I had, however, already discussed the 

 matter at some length with Darwin, and in a letter 0/ 

 September 18, 1869, I gave him my general argument as. 

 follows : — « 



" I have a general and a special argument to submit. 



" 1. Female birds and insects are usually exposed to more 

 danger than the male, and in the case of insects their exist- 

 ence is necessary for a longer period. They therefore require, 

 in some way or other, an increased amount of protection. 



"2. If the male and female were distinct species, with. 

 different habits and organizations, you would, I think, admit, 

 that a difference of colour, serving to make that one less 

 conspicuous which evidently required more protection than 

 the other, had been acquired by natural selection. 



" 3. But you admit that variations appearing in one sex. 

 are (sometimes) transmitted to that sex only. There is 

 therefore, nothing to prevent natural selection acting on the ' 

 two sexes as if they were two species. 



"4. Your objection that the same protection would, to - 



