Tlie Evidence from Sexual Characters. 233 



We must recollect, however, that the sexual passion is 

 not the only one upon which the perpetuation of the 

 species depends. The parental feeling or passion is fully 

 as important, and as a rule this is most developed in the 

 female. In the same way that the males which are best 

 fitted for pleasing and commanding the females are nat- 

 iially selected, those females which are best adapted 

 for protecting, feeding, and educating the young would 

 be picked out from generation, to generation. If auy 

 hereditary variation should appear which contributed in 

 any way to this end, it would be at least as valuable to 

 the species as an extra ornament or a new color in the 

 male; aud there are certainly as many possible ways to 

 improve a female animal as there are to improve a male. 

 If these variations of jiarts which are confined to the fe- 

 male, or which are of use only or chiefly in this sex, are 

 as apt as the similar parts of a male to give rise to 

 hereditary modifications, w^e should expect the evolution 

 of new improvements in the female body to keep jDace 

 with the improvement of the male body. 



We should expect, when allied species are compared, 

 to find that the females differ from each other as much 

 as the males; and that while the males are gradually 

 becoming more and more specialized for conflict and 

 rivalry with other males, and for winning the favor of 

 the females, the females are becoming specialized along 

 another path, for the better care and protection of their 

 youug. The fact that we find nothing of the kind; that 

 evolution shows itself especially in the males, while the 

 females remain comparatively stationary, shows that we 

 must search for some other explanation than the one 

 given by Darwin. We are, therefore, compelled to 

 recognize, in the general rule that the male is more 

 modified than the female, the evidence of some cause 



