evolution of the colors of birds. 317 



Genus Phainopepla. The Phainopepla. 



(7) Adult male more conspicuously colored than 

 female; young like female. 



Prevailing colors, bluish black, white, brownish gray. 



The male has become completely glossy blue-black, 

 with the exception of the white recognition mark on the 

 wing, while the female is a brownish gray, not having 

 yet acquired the specialization of pigmentation of the 

 male. 



FAMILY LANIID^. The Shrikes. 

 Genus Lanius. The Shrikes. 



(1) Adult male like female; young similar to adult. 



Prevailing colors, black, white, gray, brownish. 



I am unable to suggest any satisfactory explanation 

 of the colors of this genus, although the black line 

 through the sides of the head, and the black wings and 

 tail with the contrasted white are excellent recognition 

 markings. I fail to see any particular need for such 

 markings, as the birds are not very social in their habits, 

 and have no enemies to fear, in particular. Neither 

 could these be discriminative marks, for they are shared 

 in common by all the genera. Their origin must, ac- 

 cordingly, date back to some ancestral form in which 

 such characters may have been of utility. 



FAMILY VIREONID^. The Vireos. 

 Genus Vireo. The Vireos. 



(1) Adult male like female; young more or less 

 closely like adult, or (8) male slightly more conspicu- 

 ously colored than female; young with a plumage slight- 

 ly duller than female. 



Prevailing colors, black, white, olive green, brown, 

 gray, yellow. 



