EVOLUTION OF THE COLOKS OF BIEDS. 287 



becoming insignificant. Thus, in the phcebe and black 

 pewee (Sayornis phcebe and *S. nigricans) the wing bands 

 are distinct rusty, but obscured in the adult. In Say's 

 pewee (S. saya) the young has the reddish tinge much 

 brighter than the adult, and suffused over the back as 

 well as the breast. The young of the olive-sided fly- 

 catcher has the breast clear white, the streaks being more 

 restricted to the sides, while in the adult the breast is buffy 

 and heavily streaked. It seems from this as if the bird 

 of to-day had reverted from a brighter or more special- 

 ized color, to the primitive streaked style of marking. 

 In the genus Empidonax the different species were ap- 

 parently more specialized in former times, but through 

 reversion have become very closely alike in color, and 

 have lost even their distinctive recognition marks, ex- 

 cept the obscure wing bands. 



FAMILY ALAUDID^. The Larks. 



The members of this family are generally dull colored 

 birds not very highly specialized in respect to their 

 markings. Living almost exclusively on the ground, 

 when not in flight, the need for protective colors har- 

 monizing with the ground is particularly manifest. 



Genus Otocoris. The Horned Larks. 



(8) Male more conspicuously colored than female; 

 young with a peculiar first plumage. 



Prevailing colors, brown, white, black, yellow, buffy, 

 etc. 



Unlike most of the family the species of this genus 

 appear to be the descendants of a much more darkly 

 colored form. They have been modified largely by the 

 direct influences of the environment, probably in com- 

 paratively recent times, as the distinctions are in the 

 main only varietal and not specific. As usual, the dark- 



