BIRDS OF NORTH AND MIDDLE AMERICA. 179 



Bill longer than head, elongate-conical, acute, compressed, with 

 nearly straight outlines, its basal depth decidedly less than distance 

 from nostril to tip of maxilla, its basal width less than half that dis- 

 tance; culmen straight, ascending but not conspicuously elevated 

 basally, forming a broad, nearly flat, frontal shield, with rounded pos- 

 terior outline, the extreme posterior portion of which extends about 

 as far as the anterior angle of the eye; gonys straight, decidedly more 

 than half as long as culmen, but about as much shorter than distance 

 from nostril to tip of maxilla; mandibular rami widened, but not 

 swollen, posteriorly, with terminal outline truncate or faintly conca\'p; 

 commissure nearly straight. Nostril much below lateral median line 

 of maxilla, small, broadly oval or nearly circular, bored directly into 

 the horny rhinotheca, beveled off anteriorly, posteriorly touching the 

 loral feathering. Wing moderate (more than three times as long as 

 culmen), short-tipped (primaries exceeding secondaries by less than 

 length of culmen), rounded; outermost (ninth) primary intermediate 

 between fifth and fourth; seventh, or seventh and sixth, longest; four 

 outer primaries broad and rounded at tips (the first slightly contracted 

 terminally), their inner webs faintly sinuated. Tail about three- 

 fourths as long as wing, graduated, with middle pair of rectrices 

 abruptly abbreviated (intermediate in length between outermost and 

 the next), the rectrices rather narrow, but not obviously contracted 

 terminally nor pointed. Tarsus about as long as the maxilla from 

 nostril, or a little longer, stout, its anterior scutella very distinct; 

 middle toe, with claw, about as long as tarsus; outer toe with claw 

 reaching about to base of middle claw, the inner slightly shorter; 

 hallux shorter than lateral toes, but conspicuously stouter, its claw 

 slightly shorter than the digit; all the claws strongly curved. A 

 crescentic patch immediately behind frontal shield, rictal and sub- 

 orbital regions, anterior and middle portion of malar region, and sides 

 of chin and throat naked, the last separated from the naked cheek- 

 space by a narrow line of feathering; a sparse crest of narrow elon- 

 gated feathers springing from middle of crown. 



Coloration. — Black and chestnut, or yellowish olive-green, with tail 

 mostly yellow. 



Range. — Southern Mexico to Bolivia and southern Brazil. (Five 

 species, only one of them north of the Isthmus of Panama.) 



KEY TO THE SPECIES OF GyMNOSTINOPS. 



a. Winga, upper tail-coverts, and flanks chestnut. 

 h. Breast, abdomen, and thighs chestnut. ( Southern Mexico to Isthmus of Panama. ) 



Gymnostinops monteznma (p. 180) 

 hh. Breast, abdomen, and thighs black. (Northern Colombia.) 



Gymnostinops cassini (p. 181) 



aa. Wings (except a small area next to scapulars), upper tail-coverts, and flanks 



black. (Northern Colombia. ) Gymnostinops guatimozinus ( p. 182 ) 



