EVOLUTION OF THE COLORS OF BIRDS. 223 



miliar example of this class, the colors of the female 

 being much duller than those of the male, and the young 

 having a mottled breast. 



The next class (9) includes those species in which the 

 male is more conspicuously colored than the female and 

 the young of each sex resembles its respective adult. 

 The following forms are representative of the class. 



Habia ludoviciana. Sphyro^picus thyroideus. 



Picoides. Mclanerpes aurifrons. 



In the three-toed woodpeckers (Picoides) the adult male 

 differs from the female chiefly in the yellow crown patch, 

 which is lacking in the latter. The young do not 

 materially differ from the adults. In the golden-fronted 

 woodpecker (Melancrpes aurifrons) the general plumage 

 of the young is like that of the adult except that the 

 colors of the former are duller, particularly the yellow 

 of the belly. The adult female differs from the adult 

 male chiefly' in lacking the red on the head, and with 

 the yellow of the head duller. In the young male the 

 markings of the adult are indicated but very dull, while 

 the yellow of the young female is so pale as to be almost 

 buffy. Williamson's woodpecker ( Sphyrapicus thyroideus) 

 is interesting as coming one step nearer to class 10, 

 and also of note from the fact that the female is so 

 markedly different in color from the male. The young 

 female is like the adult female, having a barred plum- 

 age, but the yellow of the belly is decidedly paler. The 

 young male has the plumage marked in uniform masses 

 of black and white like the adult, but the bright yellow 

 is replaced by white and the red throat patch is lacking. 



In the rose-breasted grosbeak (Habia ludoviciana) we 

 have approached one step nearer to class 10 showing 

 how these different divisions shade into one another. 

 In this species the young male is intermediate in plum- 



