258 CALIFORNIA ACADEMY OF SCIENCES. 



exclusively to the direct influence of the environment, 

 and varying characteristically from the dark races of 

 Florida and Mexico (C. virginianus jioridanus and C. 

 graysoni), to the pale desert form of southern Arizona 

 (G. ridgwayi). 



Genus Oreortyx. Mountain Partridges. 



(2) Adult male like female; young like some ances- 

 tral stage of the adult. 



Colors — Black, white, gray, plumbeous, chestnut, 

 ochraceous. 



The varied and beautiful markings of this bird were 

 doubtless acquired by the male first, by sexual selection 

 (Epigamic) and afterwards transferred to the female. 

 They may also have been of use as recognition marks. 

 This is particularly the case with the distinct buffy or 

 ochraceous stripe on the inner web of the tertials, which 

 is?characteristic not only of this genus but also of Calli- 

 j)epla. The young are much spotted, representing an 

 ancestral stage of plumage which may still be protective, 

 blending with the lights and shadows of the forest. 



Two races, darker in the Coast Range, lighter in the 

 Sierra Nevada Mountains, from climatic influence. 



Genus Callipepla. Valley Quail. 



(8) Adult male more conspicuously colored than 

 female (usually); young with peculiar first plumage. 



Colors — Black, white, gray, brown, chestnut, buffy. 



The colors in this group are obviously sexual in their 

 nature, being partly for recognition and partly for 

 adornment. The genus is of special interest as show- 

 ing different stages of differentiation of the sexes. The 

 sexes are alike in C. squamata, the degree of specializa- 

 tion of colors being slight, and the general tendency 

 being protective. In fact, both sexes are at about the 

 degree of development of the female C. californica, the 



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