198 THE COURTSHIP OF ANIMALS 



simple interpretation. For if we consider the fact that 

 the females frequent the forests where the Heliconidae 

 abound [the distasteful species already referred to] while 

 the males fly much in the open and assemble in great 

 numbers with other white and yellow Butterflies on the 

 banks of rivers, may it not be possible that the appearance 

 of orange-stripes or patches would be as injurious to the 

 male as it was useful to the female, by making him a more 

 easy mark for insectivorous birds among his white com- 

 panions ? This seems a more probable supposition than 

 the altogether hypothetical choice of the female, some- 

 times exercised in favour of, and sometimes against, every 

 new variety of colour in her partner." 



Wallace's arguments are not so crushing as he supposed 

 them to be, and they contribute nothing towards the 

 solution of the problem to be faced. But if colour played 

 the part which Darwin believed, and colour alone be 

 concerned, it is curious that the males should recognize 

 their mates in a guise so unlike their own. How is it 

 that they do not pass them by as members of the totally 

 different distasteful species ? Whenever, indeed, the female 

 is more or less brightly liveried than the male, how do the 

 sexes recognize one another, and how, when they live 

 in environments so different as those referred to by 

 Wallace, do they find one another when possessed by 

 the insistent demands of the " sex-hunger " which is the 

 all-essential stimulant to secure the continuation of 

 the race ? 



The factors which assure the satisfaction of this hunger 

 differ in some important features from those which obtain 

 among the higher animals — birds, for example. In the 

 first place there is no necessity to find and hold territory, 

 which is an imperative necessity where there are eggs to 



