SUBFAMILY TETRAONINA. 205 
6. 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. columbt- 
J anus. 
PRAIRIE SHARP- 
6’. Ground color of upper parts rusty or ie TAILED GROUSE. 
ochraceous. I eee cam- 
yee 
GENUS CENTROCERCUS 
(Greek xevtpov, kextron, a spine; + kepkos, heros, tail). 
Centrocercus, Swain. Faun. Bor. Amer., 1831, pp. 358, 496. 
Type, Zetrao urophastanus, 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 LAGOPUS 
(Greek Xayorous, /agopus, hare foot). 
Lagopus, Briss. Ornith., vol. i., 1760, p. 181. Type, Zetrao 
lagopus, Linn. 
Tarsi and toes densely feathered. Tail rather short, slightly 
