SEXUAL SELECTION 583 



inches; in the common pheasant it is about twenty inches 

 long in the male and twelve in the female; in Scemmerring's 

 pheasant, thirty-seven inches in the male and only eight in 

 the female ; and lastly, in Reeve's pheasant it is sometimes 

 actually seventy-two inches long in the male and sixteen 

 in the female. Thus in the several species, the tail of the 

 female differs much in length, irrespectively of that of the 

 male ; and this can be accounted for, aa it seems to me, with 

 much more probability, by the laws of inheritance — that 

 is, by the successive variations having been from the first 

 more or less closely limited in their transmission to the 

 male sex — than by the agency of natural selection, resulting 

 from the length of tail being more or less injurious to the 

 females of these several allied species. 



We may now consider Mr. Wallace's arguments in re- 

 gard to the sexual coloration of birds. He believes that 

 the bright tints originally acquired through sexual selec- 

 tion by the males would in all, or almost all, cases have 

 been transmitted to the females, unless the transference 

 had been checked through natural selection. I may here 

 remind the reader that various facts opposed to this view 

 have already been given under reptiles, amphibians, fishes, 

 and lepidoptera. Mr. Wallace rests his belief chiefly, but 

 not exclusively, as we shall see in the next chapter, on the 

 following statement,* that when both sexes are colored in a 

 very conspicuous manner, the nest is of such a nature as to 

 conceal the sitting bird; but when there is a marked con- 

 trast of color between the sexes, the male being gay and 

 the female dull colored, the nest is open and exposes the 

 sitting bird to view. This coincidence, as far as it goes, 

 certainly seems to favor the belief that the females which 

 sit on open nests have been specially modified for the sake 

 of protection; but we shall presently see that there is an- 

 other and more probable explanation, namely, that conspio- 



» "Journal of Travel," edited by A. Murray, vol. i., 1868, p. 1&. 



