390 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



beneath, distinctly graduated in size, that of hallux about two-fifths 

 longer than that of outer toe; web between basal phalanges of outer 

 and middle toes distinct. 



Plumage and coloration. — Plumage in general rather compact, the 

 feathers distinctly outlined, those of head (especially on pileum) 

 sublanceolate; feathers on outer side of thighs larger than those on 

 inner side, but not forming a distinct "boot"; entire loral region prac- 

 tically nude, but with rather sparse small bristles, those of the upper 

 anterior portion longer and recurved. Adults plain black, slaty 

 black or dark slate color, the tail black, crossed by one or more broad 

 bands of white and tipped with whitish. Young variegated above 

 with blackish and ochraceous or buffy, beneath buffy or ochraceous 

 striped with dusky, the thighs barred with the same, the tail with 

 numerous narrow bands of blackish and light grayish intermixed with 

 white. 



Range. — Tropical America, from Mexico and Central America to 

 Argentina, Paraguay, and Chile. (Alonotypic.) 



KEY TO THE SUBSPECIES OF HYPOMORPHNUS 



a. Plumage, except for tail, practically wholly black. 



6. Tail with two black bars, the subterminal one the wider of the two 



(Mexico to Panama) H. urubitinga ridgwayi, ad. (p. 390) 



hb. Tail with only one black bar (a subterminal one) (e. Panama to 



Bolivia) H. urubitinga urubitinga, ad. (p. 393)^' 



aa. Plumage below bufify marked with fuscous-black. 



h. Subterminal blackish band on rectrices very broad (40 mm. or more in 



width) H. urubitinga urubitinga, imm. (p. 394) 



H. urubitinga ridgwayi, imm. (p. 391) "• 

 66. No very broad subterminal band on rectrices. 



H. urubitinga urubitinga, juv. (p. 394) 

 H. urubitinga ridgwayi, juv. p. 391) 



HYPOMORPHNUS URUBITINGA RIDGWAYI (Gurney) 



Mexican Urubitinga 



Adult (sexes alike in color). — Entire head, except for the bare 

 loreal area, and body, wings, and thighs uniform black with more or 

 less of a slaty cast, especially on the neck, breast, and back; the under 

 wing coverts and the thighs finely barred or spotted with whitish; 

 the remiges indistinctly banded with dark slate; primaries decidedly 

 exceeding the secondaries in length; the inner webs of the outer five 

 or six pairs slightly sinuated, fourth or fifth quill longest, first shorter 



8» In southern South America (Paraguay, Argentina, etc.), there is another race, 

 Hijpomorphnus urubitinga azarae, distinguished from the nominate form only by 

 its larger size. 



*> Young birds of these two races are not distinguishable with certainty. On 

 the whole, young of the nominate race average slightly larger than those of 

 ridgwayi. 



