EVOLUTION OP THE COLORS OF BIRDS. 107 



the species. Wherever the life-interests of the individ- 

 ual clash with those of the species, that individual is 

 sacrificed in favour of others who happen better to sub- 

 serve the interests of the species. For example, in all 

 organisms a greater or less amount of vigour is wasted, 

 so far as individual interests are concerned, in the form- 

 ation and the nourishment of progeny. * * * *■ Again, 

 all unselfish instincts have been developed for the sake 

 of the species, and usually against the interests of the 

 individual. An ant which will allow her head to be 

 .slowly drawn from her body rather than relinquish her 

 hold upon a pupa, is clearly acting in response to an 

 instinct which has been developed for the benefit of the 

 hive, though fatal to the individual. And, in a lesser 

 degree, the parental ins^ncts, wherever they occur, are 

 more or less detrimental to the interests of the individ- 

 ual, though correspondingly essential to those of the 

 race." 



Let us view these words of Mr. Romanes in the light 

 of what has just been said concerning the nature of a 

 species. Discarding any teleological conception as un- 

 worthy of scientific consideration, why should natural 

 selection preserve the species rather than any other more 

 or less inclusive taxonomic group? Natural selection is 

 the result of a struggle for existence. This struggle for 

 existence, as Darwin has shown, is most keen among 

 those individuals that are most alike; just as among 

 men, doctors come into closer competition with one 

 another than they do with lawyers, or a dry goods mer- 

 chant will have a harder contest with his fellow dry 

 goods merchants than he will with a hardware merchant. 

 The struggle for existence is then, first of all, a struggle 

 of individuals of one species among themselves, in 

 which battle only the fittest will survive. But how could 

 the self-sacrificing ant to which Mr. Romanes alludes. 



