1. Head and neck, above and beneath, black; their sides white.
A. A broad white stripe above the eye, meeting across forehead.
1. P. montanus. Edges of wing-coverts, secondaries, and tail scarcely paler than general tint above. Beneath ashy-whitish, medially. Wing, 2.85; tail, 2.50; bill (along culmen), .50; tarsus, .69; middle toe, .43; wing-formula, 4 = 5, 3 = 6, 7, 2; graduation of tail, .18. Hab. Mountain regions of Middle and Western United States.
B. No white stripe above the eye.
a. Tail as long as, or longer than, wing. conspicuous white edgings to wing-coverts, secondaries, and tail-feathers.
2. P. atricapillus.
Dorsal region yellowish-cinereous, wings and tail purer ash; sides light ochraceous. White edgings of tail-feathers not margining their ends. Wing, 2.60; tail, 2.60; bill, .40; tarsus, .62; middle toe, .36; wing-formula, 4, 5, 6, 3, 7, 8, 2 = 9; graduation of tail, .30. (12,851 ♂: Brooklyn, N. Y.) Hab. Eastern Province of North America, north of about 39° … var. atricapillus.
Dorsal region and sides with scarcely a perceptible yellowish tinge; white edgings of tail-feathers passing around their ends. Beneath whitish. Wing, 2.75; tail, 2.80; culmen, .35; tarsus, .65; middle toe, .40; wing-formula, 5, 4 = 6, 3 = 7, 8, 2 = 9; graduation of tail, .50. (3704 ♂? Salt Lake City, Utah.) Hab. Region of Missouri River and Rocky Mountains … var. septentrionalis.
Colors as in atricapillus, but much darker. Beneath more ochraceous. Wing, 2.40; tail, 2.50; culmen, .40; tarsus, .60; middle toe, .40; wing-formula, 4th, 5th, and 6th equal, 3 = 7, 2 = 10; graduation of tail, .25. (6762 ♂? Fort Vancouver, Washington Territory.) Hab. Pacific Province of North America … var. occidentalis.
b. Tail shorter than wing; no conspicuous white edgings to wings and tail.