23 



The dry season as compared with the wet makes greater demands 

 on the provisions for individual safety from enemies, and the dry- 

 season broods become modified accordingly. The female sex 

 demands a higher degree of protection than the male, and so 

 we see that when the same means of protection are employed 

 in common by both sexes, the female enjoys them in greater 

 measure. When the methods employed are different, the more 

 efficacious contrivance is appropriated by the female. When the 

 mode changes in correspondence with the change of season, we 

 often find the female still clinging in the time of plenty, to the 

 means of defence which enabled her to tide successfully over the 

 hazardous time of stress and adversity. 



This finishes what I have to say on the present occasion about 

 Dimorphism as exemplified in Butterflies. We may consider, I 

 think, that we have not only been able to pa=s in review a series of 

 facts which in themselves are both curious and interesting ; but, 

 what is of more importance, that we have been able in the case 

 both of seasonal and of sexual dimorphism to gain some insight 

 into the bionomic significance of this remarkable phenomenon. 



