TETRAONID^:. 



18o 



e». Tail more than two-thirds as long as wing; bill small and 

 weak, its depth at base less than length of middle claw. 



Callipepla. (Page 191.) 



e 2 . Tail less than two-thirds as long as wing; bill stouter, its 

 depth at base decidedly greater than length of middle 

 claw. 



f\ Head with a conspicuous crest of long narrow feathers 

 exceeding tarsus in length ; plumage of upper parts 

 plain olive ; wing more than 5.00. 



Oreortyx. (Page 190.) 

 P. Head not conspicuously crested, or else with longest 

 feathers much shorter than tarsus ; plumage of upper 

 parts much varied with spots, bars, and other mark- 

 ings; wing less than 5.00. 

 g\ Head not distinctly crested... Colinus. (Page 186.) 



g*. Head distinctly crested Mipsychortyx. 1 



<?. Tail much less than half as long as wing, the feathers soft, narrow at 

 tips, and hardly distinguishable from the coverts ; claws very large, 

 broad, and blunt, the middle one nearly as long as the exposed culmen. 

 Head with a full soft crest of blended feathers ; sexes exceed- 

 ingly different in colors Cyrtonyx. (Page 193.) 



At least upper half of tarsus feathered (usually feathered to toes) ; nasal fossa* 

 densely feathered ; sides of toes pectinated in winter (the points deciduous in 

 summer) ; larger (wing more than 6.00). (Subfamily Tetraoninw.) 

 b\ Legs feathered down to base of toes. 



c 1 . Tail longer than wings, graduated, the feathers narrow and pointed ; 



wing more than 10.00 Centrocercus. (Page 204.) 



c 2 . Tail shorter than wings, not graduated (or else extremely short, with 

 middle pair of feathers longer than rest), the feathers broad and 

 rounded, or nearly truncated, at tips ; wing less than 10.00. 

 d 1 . Tail about half as long as wing, graduated or much rounded. 



e 1 . Tail graduated, with middle pair of feathers projecting much 

 beyond the rest ; no tufts or other elongated feathers on 



neck Pediocaetes. (Page 203.) 



e 2 . Tail rounded, middle pair of feathers not projecting beyond 

 rest; sides of neck with a conspicuous tuft of straight, 

 rather stiff feathers, and beneath these an inflatable air-sac. 



Tympanuchus. (Page 202.) 



<P. Tail more than half as long as wing, rounded or nearly even ; no 



tufts, ruffs, or other conspicuous feathers on neck. 



e 1 . Toes feathered; tail less than two-thirds as long as wing; 



plumage becoming chiefly or entirely pure white in 



winter Lagopus. (Page 198.) 



1 Euptychorlyx GouiJ), lion. OJont. 1850, 15. Type, Tetrao critlattu Lisx. 



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