Ch. Sp. ♂ Similis O. imberbi, sed rostro robustiore; colore obscuriore ac magis cinerario.
Adult ♂ (No. 6000, author’s collection—collector’s No. 313. Tucson, May 1, 1881. F. Stephens). Above ashy brown; crown nearly pure brown in decided contrast with the back; rump pale brown with a faint olive tinge; wings and tail brown, edged with ashy-white; greater and middle wing-coverts tipped with fulvous, forming two wing-bars; edge of wing and under wing-coverts pale lemon-yellow; lores and sides of head posteriorly, ashy; a narrow frontal line continued backward above and nearly around the eye, ashy-white; under parts ash, shading posteriorly to ashy-white on the belly, and with the faintest possible lemon tinge on the jugulum and crissum; bill stout; upper mandible much curved, brown; under mandible slightly curved, brown at tip, brownish-orange at base; commissure reddish-orange.
Dimensions. Length, 4.60; extent, 7.20; wing, 2.23; tail, 1.96; culmen, .42; tarsus, .56; depth of bill at nostrils, .15.
Adult ♀ (No. 6133, author’s collection—collector’s No. 446. Tucson, May 28, 1881. F. Stephens). Smaller than the male, slightly more yellowish below and with a faint tinge of olive on the back.
Dimensions. Length, 4.50; extent, 6.70; wing, 2.04; tail, 1.78; culmen, .40; tarsus, .52; depth of bill at nostrils, .14.
Juv., first plumage, ♂ (No. 6138, author’s collection—collector’s No. 451. Tucson, May 29, 1881. F. Stephens). Crown plumbeous; back olive-brown; wing and tail-coverts, outer edges of secondaries, and a broad tipping on all the rectrices, dull brownish-chestnut; beneath delicate ashy-buff, shading to yellowish-white on the belly and crissum; bill orange, dusky at tip of upper mandible.
Habitat, Arizona.
The chief points of difference between the above race and imberbe proper may be briefly expressed as follows:
O. imberbe.—Depth of bill at nostrils, .11 to .13. Above olivaceous-ash; entire under parts strongly tinged with lemon-yellow.
O. imberbe ridgwayi.—Depth of bill at nostrils, .14 to .15. Above ashy brown; beneath ash or ashy-white with scarcely any yellowish.