SEXUAL COLOUR 87 



nesting cannot alone account for such great 

 differentiation, for when males incubate, 

 females are never more than slightly more 

 conspicuously coloured. It appears, there- 

 fore, that the difference in value between the 

 sexes, or some other factor, must be looked 

 for to explain this. 



As with parental colour, so with sexual 

 colour conspicuous colours among preda- 

 tory animals, or among night animals, would 

 not be anticipated, nor is it found. 



So also sexual dimorphism should, accord- 

 ing to the theory, not be found in aposematic 

 animals, nor is it at all common ; because, 

 having few enemies, they are not very liable to 

 attack. Sometimes secondary sexual char- 

 acters occur before sexual maturity, as in the 

 upland Goose (Chloephaga Magellanica). In 

 this case one would conclude that the society 

 feels the great value of the female even at 

 this early stage. 



Worthy of note and favouring the theory is 

 the fact that in mimicry it is often only the 

 female which seeks protection in this way; 

 the male, it would seem, purposely refraining 

 from doing so, in order that, should the pair 

 be attacked during mating or copulation, he 

 will be destroyed at the saving of the female. 



