EPIGAMIC ORNAMENTATION 349 



Frequenters of any good museum of natural history will be 

 familiar with plenty of examples of epigamic ornamentation. 

 The highly elaborate and gorgeous plumage of many male birds, 

 such as the peacock, the Argus pheasant, the Australian lyre- 

 bird (Fig. 178) and numerous species of humming birds, to say 

 nothing of less conspicuous examples, affords the best illustration 

 of this phenomenon. In all such cases the function of the 

 ornamentation appears to be to gratify the aesthetic sense of the 

 female during the period of courtship, and render her amenable 

 to the attentions of her mate. There is no doubt that in many 

 cases the cock bird deliberately displays himself to the best 

 advantage before the admiring eyes of the hen, who is credited 

 with a no less deliberate choice of the partner who most nearly 

 approaches her ideal standard of beauty. In all these cases the 

 plumage of the female is comparatively sombre and uninteresting. 

 An elaborate and gaudy tail would be a disadvantage during 

 the lengthy period of incubation, when it is desirable, both 

 for her own sake and that of her offspring, that the female 

 should be as inconspicuous as possible. Thus it is the male bird 

 that has had to adapt his clothing to the requirements of the 

 female, and she herself is unable to follow the fashions which she 

 imposes upon her mate. 



It is obvious that no theory of evolution can be regarded as 

 satisfactory which does not offer some explanation of the origin of 

 such highly specialized and precise adaptations as those which we 

 have been considering in this chapter, and it was in order to 

 emphasize the need for such explanation that we have laid so 

 much stress upon them. We shall see in our next chapter that 

 no less remarkable and precise adaptations for special purposes 

 are also met with in the vegetable kingdom, and shall then pass 

 on to seek the necessary explanation. 



