SEXUAL COLOUR 85 



become conspicuous in order to be killed, 

 only less conspicuous ones will be left to 

 carry on the species, and conspicuousness 

 will thus be quickly eradicated by Natural 

 Selection. 



It is obvious that this criticism cannot be 

 levelled at the author's theory, which in some 

 respects is not unlike Stolzmann's. The 

 author's theory deals with the pair, male and 

 female associated together at the breeding 

 season or during copulation ; under these con- 

 ditions the destruction of a conspicuous male 

 by no means precludes that his characters will 

 not be handed down to the next generation. 

 He most probably will have already fertilised 

 the female either partially or entirely. It 

 may here be noted that secondary sexual 

 characters are at their highest development 

 at the time when the female is ready to be 

 fertilised ; male birds, for instance, are in their 

 most brilliant plumage, not during their nest- 

 ing season, but at a considerable time before 

 this, in either the last of winter or the first 

 of spring. 



The relative proportion of males to females 

 is, as Stolzmann concludes, a most important 

 factor in the welfare of the species. Accord- 

 ing to the theory, great excess of males 



