Ammodromus. Bill slender, small at base, and elongated. Tertials not longer than the secondaries; rounded at the tip. Claws large, hinder one equal to its digit. Outstretched toes reaching considerably beyond the end of the stiffened, almost scansorial tail.
B. Tail longer and broader; nearly or quite as long as, sometimes a very little longer than, the wings, which are rather lengthened. The primaries considerably longer than the secondaries. None of the species streaked beneath, and the back alone streaked above. (Spizelleæ.)
a. Tail rounded or slightly graduated.
Chondestes. Tail considerably graduated, not emarginated. Lateral toes considerably shorter than the middle toe, without its claw. Wings very long, decidedly longer than the tail, reaching the middle of the
tail. First quill longest. Head striped. Back streaked. White beneath. A white blotch on the end of the tail-feathers.
Zonotrichia. Tail moderately graduated. Wings moderate, about as long as the tail, reaching about over the basal fourth of the tail; first quill less than the second to fourth. Feet large. Head striped with black and white, or with brown and ochraceous. Back streaked.
Junco. Tail very nearly equal to the wings, slightly emarginate, and decidedly rounded. Outer toe rather longer than inner, reaching the middle claw. No streaks anywhere except in young; black or ash-color above; belly white; with or without a rufous back and sides. Outer tail-feathers white.
Poospiza. Tail lengthened, slightly graduated; the feathers unusually broad to the end. Bill slender. Wings about as long as the tail, reaching but little beyond its external base. Tertials broad, and, with the secondaries, rather lengthened. Second to fifth quills nearly equal, and longest. Bill dark lead-color. Tail black. Uniform ashy-brown above; white beneath. Sides of head with stripes of black and white.
b. Tail decidedly forked; a little shorter than the wing, sometimes a little longer.
Spizella. Size rather small. Wings long. Lower mandible largest. Uniform beneath, or with a pectoral spot or the chin black.