EVOLUTION OP THE COLORS OF BIRDS. 147 



Parabuteo unicinctus liar- Arclnbuteo lagopus sancti- 



risi. joltunnis. 



Buteo harlani. Geophloeus pileatus. 



Buteo abbreviatus. Leucosticte airata. 



Buteo sivainsoni. Junco hyemcdis. 



Buteo fuliginosus. Sayornis nigricans. 



Falco columbarius sucldeyi. 



There are thus something like forty-five or fifty North 

 American species which show a very strong tendency 

 toward melanism. The relation of geographical distri- 

 bution to this subject will be discussed at a later stage of 

 our inquiry. Besides these species in which black is 

 the sole or predominant hue, there are a number in 

 which it figures quite largely. Thus the genus Pipilo 

 contains two groups, erythro23hthalmufi and maculatus in 

 which the back, throat and breast are mainly black. 

 The American redstart Setophaga riUicella has the black 

 distributed in precisely the same manner, while in the 

 painted redstart (S. picta) there is a still greater pre- 

 dominance of black. Indeed, there is a curious paral- 

 lelism between the colors in these two widely separated 

 genera which may be only a coincidence or may be a 

 matter of profound significance. At any rate it is a 

 subject of great importance in an investigation like the 

 present, to scrutinize all these apparent coincidences 

 and see if they may not have some real meaning. In the 

 first place, then, Pipilo erythrophthalmus and Setophaga 

 ruticilla both have the black of the male distributed 

 over the same parts of the body. There is the same 

 abrupt contrast between the black of the breast and the 

 white of the belly. The sides of the breast are red in 

 both species, although in the one it is a bright fiame 

 reddish-orange (Setophaga) while in the other it is chest- 

 nut or rufous. There is a light patch on the wing, 

 orange in Setophaga and white in Pipilo. The tail 



