440 U. 8 P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
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; 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 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. 
SprzeLua.—Size rather small. Wings long. Lower mandible largest. Uniform 
beneath, or with a pectoral spot or black chin, 
C.—Tail lengthened and graduated ; decidedly longer than the wings, which are very short, 
scarcely extending beyond the external base of the tail. Feet reaching but little beyond the 
middle of the tail. Species all streaked above; streaked or nearly unicolor beneath. No white 
on wings or tail. Outer lateral toe the longer. First quill not the shortest of the primaries. 
Metosp1zA.—Culmen and commissure nearly straight. Claws stout; hinder one 
as large as its digit. Tail feathers rather broad. Body streaked beneath. 
PrucaEA.—Culmen and commissure curved. Claws weak; hinder one not much 
curved, decidedly shorter than its digit. Tail feathers narrow. Without streaks 
beneath, excepting a narrow maxillary stripe. 
D.—Tail rather short, and much graduated ; longer than the wings ; the midrib more median. 
Culmen curved. Tarsus considerably longer than middle toe. Outer toe longer. But little 
difference in the length of the quills; the outer ones much rounded ; even the second quill is 
shorter than any other primary except the first. 
EmBerNaGRA.—Color, olive green above. 
CENTRONYX, Baird. 
Cu.—Bill elongated ; the lower mandible smaller ; outlines nearly straight. Tarsus lengthened, considerably exceeding the 
middle toe. Lateral toes equal, not reaching the base of the middle claw. Hind toe very large; the claw rather longer than 
its digit, and in its elongation resembling Plectrephanes, but more curved; the digit and claw together rather longer than the 
middle toe and claw. Wings very long, reaching beyond the middle of the tail, and beyond the end of the coverts. Tertials 
shorter than the primaries, and but little longer than the secondaries. Tail short, much less than from the carpal joint to end 
of secondaries; little more than two-thirds the entire wing. It is slightly forked, and moderately rounded laterally ; the 
feathers all acute. Color somewhat as in Passerculus. 
This genus differs from Passerculus, as stated in the Aeon thon of the species further on. It 
would be taken for Plectrophanes on account of its lengthened hind claw, which, however, is 
more curved than in that genus ; the tarsi are much longer, the tertials less elongated, and the 
coloration different, though closely resembling that of the female Plectrophanes. 
