592 SEXUAL SELECTION. [Pabt II 



In all cases when the more common form of equal in- 

 heritance 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 processeB 

 were carried on simultaneously, they would tend to neu- 

 tralize each other. As far as I can see, it would be ex- 

 tremely difficult to change through selection the one form 

 of inheritance into the other. But, by the selection of suc- 

 cessive variations, which were from the first sexually lim- 

 ited in their transmission, 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 fe- 

 males alone. In this latter manner female butterflies and 

 moths may, as I fully admit, have been rendered incon- 

 spicuous for the sake of protection, and widely different 

 from their males. 



Mr. Wallace 22 has argued with much force in favor of 

 his view that, when the sexes differ, the female has been 

 specially modified for the sake of protection; and that 

 has been effected by one form of inheritance, namely, the 

 transmission of characters to both sexes, having been 

 changed through the agency of natural selection into the 

 other form, namely, transmission to one sex. I was at 

 first strongly inclined to accept this view; but, the more I 

 have studied the various classes throughout the animal 

 kingdom, the less probable it has appeared. Mr. Wallace 

 urges that both sexes of the Heliconidce, Dana idee, Acra- 

 eidce, are equally brilliant because both are protected 

 from the attacks of birds and other enemies, by their of- 

 fensive odor; but that in other groups, which do not 

 possess this immunity, the females have been rendered 



22 A. R. Wallace, in 'The Journal of Travel,' vol. i. 1868, p. 88. 

 •Westminster Review/ July, 186*7, p. 37. See also Messrs. Wallace and 

 Bates in 'Proc. Ent. Soc*.' Nov. 19, 1866, p. xxxix. 



