This genus is confined to the western portions, where a single species, C. mexicanus, occurs in two well-marked varieties:—
C. mexicanus.
Culmen almost straight, the tip decurved, gonys straight. Above blackish-brown; wings and back sparsely sprinkled with minute white specks; no such markings on head or neck. Bars on tail very broad, .12 in width on outer feathers. Wing, 2.84; tail, 2.40; culmen, .96; tarsus, .75; middle toe, .68; posterior, .47; outer, .52; inner, .49 (52,791, Mazatlan, Mexico). Hab. Mexico … var. mexicanus.
Culmen and gonys both gently curved, the latter somewhat concave. Above cinnamon-ashy, more reddish on rump and wings; head and neck above with numerous dots of white; very few of these on back and wings. Tail-bars very narrow and thread-like. Wing, 2.48; tail, 2.12; culmen, .83; tarsus, .56; middle toe, .52; posterior, .35; outer, .44; inner, .36 (53,425 ♂, Fort Churchill, Nevada). Hab. Middle (and Pacific?) Province of United States … var. conspersus.
Catherpes mexicanus.
In var. mexicanus the white of throat is more abruptly defined against the rufous of abdomen than in var. conspersus, in which the transition is very gradual. The latter has the secondaries rufous with narrow isolated bars of black; the former has them blackish, indented on lower webs with dark rufous. In mexicanus the feet are very stout, and dark brown; in conspersus they are much weaker, and deep black.
All specimens from south of the United States (including Giraud’s type of Certhia albifrons) belong to the restricted mexicanus, while all from the United States are of the var. conspersus.
Catherpes mexicanus, var. conspersus, Ridgway.
CAÑON WREN; WHITE-THROATED ROCK WREN.