SUBFAMILY TETRAONIN^. 205 



b. General plumage lighter, pale brown 

 predominating. 



] COLUMBIAN 



a . Ground color of upper parts grayish sharp-tailed 

 clay color, with but little of a rusty \ grouse. 

 tinge. P. p. colutnbz- 



anus. 



>, PRAIRIE SHARP- 



b' . Ground color of upper parts rusty or [ tailed grouse. 

 ochraceous. j P. p. cam- 



J pestris. 



GENUS CENTROCERCUS 



(Greek Kevrpov, kentron, a spine; + K^pKO'i,kerkos,\.aJ(\). 



Centrocercus, Swain. Faun. Bor. Amer., 1831, pp. 358, 496. 

 Type, Tetrao urophasianus, Bonp. 



No crest. Enormous air sacs present of irregular contour, 

 fringed above by hairlike filaments, below covered with horny 

 white feathers like scales, varying with the seasons according to 

 the wear of the feathers. Tail very long, composed of twenty stiff, 

 narrow, graduated acuminate feathers. Bill large and strong. 

 Tarsi feathered to the toes. Sexes similar in plumage, but of 

 greatly disproportionate size; the female being very much the 

 smaller. 



But one species is contained in this genus, the remarkable 

 Sage Cock, or Cock-of-the-Plains, with the exception of the 

 Capercailzie of the Old World, the largest species of the sub- 

 family, indeed almost equaling in bulk that giant of the Grouse 

 Tribe. It inhabits the sage plains of the West, subsisting mainly 

 upon the leaves of that plant, which give to the flesh an exceed- 

 ingly bitter taste. It is exclusively a terrestrial species, and it 

 has a vigorous, well-sustained flight, consisting of several rapid 

 beats of the pinions, succeeded by sailings with the wings held 

 stiff and motionless. It is an unique species, and has no par- 

 ticularly near relative. It goes in flocks, and at times exhibits 

 no fear of man. 



GENUS LA GO PUS 



(Greek Xa707roi;s, lagopus, hare foot). 



Lagopus, Briss. Ornith., vol. i., 1760, p. 181. Type, Tetrao 

 lag opus, Linn. 

 Tarsi and toes densely feathered. Tail rather short, slightly 



