The Wallace-Darwin Correspondence 



line to sexual selection in the summary to the Westminster 

 Review, but the result at first to my mind was that you 

 attributed hardly anything to its power. In your penulti- 

 mate note you say : '* In the great mass of cases in which 

 there is great differentiation of colour between the sexes, 

 I believe it is due almost wholly to the need of protection 

 to the female.'^ Now, looking to the whole animal king- 

 dom I can at present by no means admit this view; but 

 pray do not suppose that because I differ to a certain 

 extent, I do not thoroughly admire your several papers 

 and your admirable generalisation on birds' nests. With 

 respect to this latter point, however, although following 

 you, I suspect that I shall ultimately look at the whole 

 case from a rather different point of view. 



You ask what I think about the gay-coloured females 

 of Pieris : ' I believe I quite follow you in believing that 

 the colours are wholly due to mimicry; and I further 

 believe that the male is not brilliant from not having re- 

 ceived through inheritance colour from the female, and 

 from not himself having varied; in short, that he has not 

 been influenced by Selection. 



I can make no answer with respect to the elephants. 

 With respect to the female reindeer, I have hitherto looked 

 at the horns simply as the consequence of inheritance not 

 having been limited by sex. 



Your idea about colour being concentrated in the smaller 

 males seems good, and I presume that you will not object 

 to my giving it as your suggestion. — Believe me, my dear 

 Wallace, with many thanks, yours very sincerely, 



Ch. Darwin. 



Wallace's more recent views on the question of Natural 

 Selection and Sterility may be found in a note written by 



» See Westminster Review, July, 1867, p. 37. 

 217 



