SECONDARY SEXUAL CHARACTERS 



119 



RED VERSUS WHITE EYES. 



GRAY VERSUS YELLOW COLOR. 



were repeated with a new type that had yellow wings. 

 The gray male is more successful and the yellow females 

 less resistant. The results are in accord with the as- 

 sumption that greater vigor is an important factor 

 in success. 



The following mating bears on this point. Stur- 

 tevant used in competition a red- and a vermilion- 

 eyed male. The latter seems as vigorous as is the 

 red-eyed type. The results were : 



Red 



Red $ 

 Vermilion $ 



11 



14 



showing that the red-eyed male has no advantage 

 when the males are equally vigorous. 



This evidence, taken as a whole, seems to me to show 

 with some probability that sight plays a minor role in 



