SEXUAL SELECTION C71 



wliite ear tufts, certainly add, as the Duke ot Argyll ad- 

 mits, to the beauty of the male; and whiteness is appar- 

 ently appreciated by other birds, as may be inferred from 

 Buoh cases as the snow-white male of the Bell-bird. The 

 statement made by Sir K. Heron should not be forgotten, 

 namely, that his peahens, when debarred from access to 

 the pied peacock, would not unite with any other male, and 

 during that season produced no offspring. Nor is it strange 

 that variations in the tail-feathers of the Urosticte should 

 have been specially selected for the sake of ornament, for 

 the next succeeding genus in the family takes its name of 

 Metallura from the splendor of these feathers. We have, 

 moreover, good evidence that humming-birds take especial 

 pains in displaying their tail-feathers; Mr. Belt," after de- 

 scribing the beauty of the Florisuga mellivora, says, "I have 

 seen the female sitting on a branch, and two males display- 

 ing their charms in front of her. One would shoot up like 

 a rocket, then suddenly expanding the snow-white tail, 

 like an inverted parachute, slowly descend in front of her, 

 - turning round gradually to show off back and front. . . . 

 ^he expanded white tail covered more space than all the 

 rest of the bird, and was evidently the grand feature in 

 the performance. While one male was descending, the 

 other would shoot up and come slowly down expanded. 

 The entertainment would end in a fight between the two 

 performers; but whether the most beautiful or the most 

 pugnacious was the accepted suitor, I know not." Mr. 

 Gould, after describing the peculiar plumage of the Uro- 

 sticte, adds, "that ornament and variety is the sole object 

 I have myself but little doubt." " If this be admitted, we 

 can perceive that the males which during former times were 

 decked in the most elegant and novel manner would have 

 gained an advantage, not in the ordinary struggle for life, 

 but in rivalry with other males, and would have left a larger 

 Dumber of offspring to inherit their newly acquired beauty. 



•» "The Naturalist in Nicaragua," 18M, p. IH. 

 » "Itttroduotion to the TroehiUda," 1861, p. IIO. 



