88 SEXUAL SELECTION: BIRDS. [Part II. 



at once resembles the ornament called a ball and socket. 

 These feathers have been shown to several artists, and all 

 have expressed their admiration at the perfect shading. 

 It may well be asked, Could such artistically-shaded orna- 

 ments have been formed by means of sexual selection ? 

 But it will be convenient to defer giving an answer to 

 this question until we treat in the next chapter of the 

 principle of gradation. 



The primary wing-feathers, which in most gallinaceous 

 birds are uniformly colored, are in the Argus pheasant 

 not less wonderful objects than the secondary wing-feath- 

 ers. They are of a soft brown tint with numerous dark 

 spots, each of which consists of two or three black dots 

 with a surrounding dark zone. But the chief ornament is 

 a space parallel to the dark-blue shaft, which in outline 

 forms a perfect second feather lying within the true feath- 

 er. This inner part is colored of a lighter chestnut, and 

 is thickly dotted with minute white points. I have shown 

 this feather to several persons, and many have admired it 

 even more than the ball-and-socket feathers, and have de- 

 clared that it was more like a work of art than of Nature. 

 Now these feathers are quite hidden on all ordinary occa- 

 sions, but are fully display^ when the long secondary 

 feathers are erected, though in a widely-different manner; 

 for they are expanded in front like two little fans or 

 shields, one on each side of the breast near the ground. 



The case of the male Argus pheasant is eminently in- 

 teresting, because it affords good evidence that the most 

 refined beauty may serve as a charm for the female, and 

 for no other purpose. We must conclude that this is the 

 case, as the primary wing-feathers are never displayed, 

 and the ball-and-socket ornaments are not exhibited in full 

 perfection, except when the male assumes the attitude of 

 courtship. The Argus pheasant does not possess brilliant- 

 colors, so that his success in courtship appears to have 



