208 Heredity. 



the difficulty larger birds would have in concealing 

 themselves if they called the attention of their enemies 

 by loud notes. He also says that he conceives it is for 

 the same reason that no hen bird sings, because this 

 talent would be still more dangerous during incubation, 

 and he suggests that the inferiority of the female bird 

 in point of plumage may be due to the same cause. 



This argument, that the dull color and lack of orna- 

 ment in female birds is a direct adaptation to their 

 peculiar life, has been elaborated by Wallace. (On 

 Natural Selection, p. 231.) He says that in the struggle 

 for existence incessantly going on, protection or con- 

 cealment is one of the most general and most effectual 

 means of maintaining life, and it is by modifications of 

 color that this protection can be most readily obtained, 

 since no other character is subject to such numerous 

 and rapid variations. He says that, as a general rule, 

 the female butterfly is of dull and inconspicuous colors, 

 even when the male is most gorgeously arrayed, and that 

 in all these cases the difference can be traced to the 

 greater need of protection for the female, on whose con- 

 tinued existence, while depositing her eggs, the safety 

 of the race depends. 



Since a male insect is, by its structure and habits, 

 less exposed to danger, it does not need any special 

 means of protection, as the female does, to balance the 

 greater danger to which she is exposed, and Wallace be- 

 lieves that on account of this danger, and because of her 

 greater importance to the existence of the species, the 

 female insect always acquires this protection in one way 

 or another through the action of natural selection. 



He also says that " the female bird, while sitting on 

 her eggs in an uncovered nest, is much exposed to tin 

 attacks of enemies, and any modification of color whicl 



