86 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



chaetura drab and tipped with white (sometimes the dark bands are 

 wanting) ; cervical sac in breeding season purplish and only slightly 

 carunculated. 



Adult female. — Similar to that of D. o. sierrae, but the sides and flanks 

 are very much more marked with white (tips, bars, and shafts of the 

 feathers) and with a much broader and clearer gray terminal band on 

 the rectrices. 



Immature male. — Like the adult but with narrower retrices, more 

 graduated tail, and often with some juvenal feathers running on the 

 head, nape, and wings. 



Immature female. — Like the adult but with narrower rectrices, more 

 graduated tail, and often with some juvenal feathers remaining on the 

 head, nape, and wings. 



Juvenal (sexes alike). — Similar to that of D. o. pallidus, from which it 

 is not certainly distinguishable. 



Downy young (sexes alike). — Like that of D. o. r'lchardsonii but 

 slightly more ochraceous-tawny above. ^^ 



Adult imle.—Wmg 221-243 (232.5) ; tail 148-192 (168.7) ; exposed 

 culmen 18.3-23.1 (21.2); tarsus 41.1-46.8 (43.1); middle toe without 

 claw 38.4-46.5 (44.8 mm.).8» 



Adult female.— Wing 197-229 (212.1) ; tail 123-153 (142.3) ; exposed 

 culmen 16-23.8 (18.9) ; tarsus 36.6-41.5 (39.9) ; middle toe without claw 

 36-41 (38.8 mm.). 90 



7?an(7^.— Resident in the Rocky Mountan region from southern Mon- 

 tana, central Wyoming, western South Dakota and northern Colorado 

 south through northeastern Nevada, and Utah to northern Arizona and 

 west-central New Mexico. 



Type locality. — "Defile Creek," about 20 miles north of Colorado 

 Springs, Colo. 



Tetrao obscurus S.'W, in Long's Exped. Rocky Mountains, ii, 1823, 14 (near 

 "Defile Creek," about 20 miles north of Colorado Springs, Colo.). — Bonaparte, 

 Ann. Lye. Nat. Hist. New York, ii, pt. 1, 1826, 127; ii, 1828, 4^-2; Contr. 

 Maclurian Lye, i, 1827, 23; Amer. Orn., iii, 1828, 27, pi. 18; Geogr. and 

 Comp. List, 1838, 43. — Lesson, Traite d'Orn., 1831, 503.— Nuttall, Man. Orn. 

 United States and Canada, Land Birds, 1832, 666; ed. 2, 1840, 809.— Wood- 

 house, Rep. Sitgreaves Expl. Zuiii and Colorado R., 1853, 96 (mountain near 

 Santa Fe, N. Mex.).— Baird, Rep. Pacific R. R. Surv., ix, 1858, 620, part 

 (Black Hills and Laramie Peak, Wyo.) ; Cat. North Amer. Birds, 1859, No. 

 459, part. — Gray, List Birds Brit. Mus., pt. 5, Gallinae, 1867, 86, part. — Allen, 

 Bull. Mus. Comp. Zool., iii, 1872, 164 (Mount Lincoln, Colo.), 170 (Wahsatch 

 Mountains, Utah, near Ogden), 181, part (mountains of Colorado and Utah). — 



" See col. fig., Moffitt, Auk, Iv, 1938, pi. 19, fig. 1. 



** Sixteen specimens from Wyoming, Utah, Colorado, Nebraska, New Mexico, 

 and Arizona. 

 ^ Ten specimens from Montana, Colorado, Utah, New Mexico, and Arizona. 



