TETRAONID^> THE GROUSE, ETC. 7 



The subfamily is most numerously developed in North America, 

 its other representatives belonging to the colder portions of 

 Europe and Asia. Of the genera included in the following ana- 

 lytical table all but one are to be found either within or very 

 near to the geographical field of the present work. 



A. Lees feathered to and on the basal membrane of the toes, which are bare. No ruff 

 on the side of the neck, which, however, has an extensible bare space. 

 Dendragapus. Tail broad, nearly even, or truncate, and rounded laterally, two thirds 

 the wing. Nasal fossae scarcely half the culmen. 



Centrocercus. Tail excessively lengthened and cuneate ; longer than the wings, the 

 feathers acuminate. Nasal fossae two thirds the culmen. Shafts of feathers on the 

 lower throat very spinous in the male. 



Pediocaetes. Tail very short, but graduated, and with the two middle feathers (per- 

 haps tail-coverts) lengthened beyond the rest, and two thirds as long as the wing ; 

 the next longest half the wing. Nasal fossae not half the length of culmen. Shafts 

 of throat feathers normal. 



B. Legs feathered to the lower end of tarsus. 



Tympanuchus. Tail very short, truncate, but laterally graduated; half as long as the 

 wings. Sides of neck with long, narrow, and rather stiff feathers. Nasal fossae 

 scarcely one third the culmen. 



C. Legs feathered to the claws. 



Lagopus. Tail about two thirds the wing, truncate, of sixteen to eighteen feathers. 

 Most species becoming white in winter; none of the other genera exhibiting this 

 peculiarity. 



D. Lower half of tarsi bare, with two rows of scutellae anteriorly. 



Bonasa. Sides of neck with ruff of broad, truncate, soft feathers. Tail very broad, 

 square or slightly rounded, as long as the wings. 



GENUS BONASA STEPHENS. 



Bonasa STEPHENS, Shaw's Gen. Zool, xi. 1819,298. Type, Tetrao bonasia LINN. 



Tetrastes KEYS. & BLAS. Wirb. Europ. 1840, p. Ixiv. 



GEN. CHAR. Tail fan- shaped, its feathers very broad, soft, as long as the wings ; eighteen 

 in number. Tarsi naked for the lower half ; covered with two rows of hexagonal scales 

 anteriorly. Sides of toes strongly pectinated. Side of neck with a tuft of very broad soft 

 feathers. Portion of culmen between the nasal fossae about one third the total length. Top 

 of head with soft crest. 



Although but one species of this genus has been detected in 

 North America, this has a very extensive range, embracing nearly 

 the entire continent; all the wooded portions, in fact, excepting, 

 perhaps, the extreme southern parts. As is often the case with 

 birds whose range covers a large extent of territory, this species 

 varies remarkably in color in the different portions of its habi- 

 tat; northern specimens and those from the Rocky Mountains 

 having almost invariably ash-gray tails, with the whole plumage 

 of a decidedly grayish cast, while specimens from the grandly tim- 

 bered and reekingly moist region of the northwest coast (Oregon 

 to Sitka) have the tails dark ferruginous, while rich rusty 



