420 THE DESCENT OF MAN 



obscure colors, or a greater number of males bj being 

 brightly colored and thus finding partners, succeeded in 

 leaving more numerous offspring. 



In order to account for the frequent transmission of 

 characters to one sex alone, Mr. Wallace expresses his 

 belief that the more common form of equal inheritance by 

 both sexes can be changed through natural selection into 

 inheritance by one sex alone, but in favor of this view I 

 can discover no evidence. We know, from what occurs 

 under domestication, that new characters often appear, 

 which from the first are transmitted to one sex alone ; and 

 by the selection of such variations there would not be the 

 slightest difficulty in giving bright colors to the males alone, 

 and at the same time, or subsequently, dull colors to the 

 females alone. In this manner the females of some butter- 

 flies and moths have, it is probable, been rendered incon- 

 spicuous for the sake of protection, and widely different 

 from their males. 



I am, however, unwilling without distinct evidence to 

 admit that two complex processes of selection, each requir- 

 ing the transference of new characters to one sex alone, 

 have been carried on with a multitude of species — ^that the 

 males have been rendered more brilliant by beating their 

 rivals, and the females more dull-colored by having escaped 

 from their enemies. The male, for instance, of the common 

 brimstone butterfly (Gonepteryx) is of a far more intense 

 yellow than the female, though she is equally conspicuous; 

 and it does not seem probable that she specially acquired 

 her pale tints as a protection, though it is probable that 

 the male acquired his bright colors as a sexual attraction. 

 The female of Anthocharis cardamines does not possess the 

 beautiful orange wing- tips of the male; consequently she 

 closely resembles the white butterflies (Pieris) so common 

 in our gardens; but we have no evidence that this resem- 

 blance is beneficial to her. As, on the other hand, she 

 resembles both sexes of several other species of the genua 

 inhabiting various quarters of the world, it is probable that 



