INSECTS. 365 



inheritance by both sexes has prevailed, the selection of 

 bright-colored males would tend to make the females 

 bright colored ; and the selection of dull-colored females 

 would tend to make the males dull. If both processes 

 were carried on simultaneously, they would tend to coun- 

 teract each other ; and the final result would depend on 

 whether a greater number of females from being well pro- 

 tected by obscure colors, or a greater number of males by 

 being brightly colored and thus finding partners, succeeded 

 in leaving more numerous offspring. 



In order to account for the frequent transmission of char- 

 acters 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 domestica- 

 tion 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 butterflies and moths 

 have, it is probable, been rendered inconspicuous 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 Aiithocharis cardamines does not possess 

 the beautiful orange wing-tips of the male ; consequently 

 she closely resembles the white butterflies (Pieris) so com- 

 mon in our gardens; but we have no evidence that this 

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

 resembles both sexes of several other species of the genus 

 inhabiting various quarters of the world, it is probable that 



