BIEDS OF NORTH AND MIDDLE AMERICA. 393 



curved terminally, indistinctly ridged; gonys about twice as long as 

 mandibular rami, straight or faintly convex basaUy, more or less con- 

 cave termiuaUy, indistinctly ridged or narrowly rounded terminally, 

 broadly rounded basally;. commissure more or less strongly arched 

 though nearly straight basally, the tomia smooth. Nostril small, 

 ovoid, obliquely vertical, in anterior end of nasal fossa. Feathers all 

 around base of bill long, bristle-like, antrorse, those at base of maxUla 

 decurved, those of chin recurved. Wing moderate, the longest pri- 

 maries more or less distinctly longer than longest secondaries; fifth 

 to seventh (usually the sixth, rarely the seventh) primary longest, 

 the ninth not longer than third, sometimes shorter than second, the 

 tenth (outermost) more than half as long as ninth. Tail six-sevenths 

 to quite as long as wing, rounded (lateral rectrices about five-sixths 

 to six-sevenths as long as middle pair), the rectrices rather broad and 

 firm, broadly rounded at tip. Tarsus longer than outer anterior toe 

 without claw. 



Coloration and plumage. — Plain slate color or slate-gray deepening 

 into black on primaries, tail and head (sometimes on back, scapulars, 

 and wing-coverts also), sometimes with white on lesser wing-coverts 

 or under wing-coverts, sometimes with forehead and chin white or 

 fulvous; in one species the wing-coverts light gray; biU red, orange, 

 or yellow. 



Range. — Nicaragua to eastern Ecuador, Bolivia, southeastern 

 Brazil, and Cayenne. (Twelve or more species.) 



KEY TO THE SPECIES OP MONASA." 



a. No white on wings; back slate color. 

 h. Fore part of head partly white (adults) or rusty (young), 

 c. Forehead, lores, and chin white or rusty. 

 d. Malar apex black, 

 e. Larger (wing 133-149.5, averaging 139.8 in male, 144.3 in female; exposed 

 culmen 35-45, averaging 37.1 in male, 38.5 in female); lower throat, 

 crown, and occiput black; white "capistrum" larger. (Eastern Costa 



Rica and eastern Nicaragua) Monasa grandioi (p. 395). 



ee. Smaller (wing, 121.5-132.5, averaging 127.6; exposed culmen, 31.5-33.5, 

 averaging 32.5); lower throat, crown, and occiput slate color or slate- 

 gray. (Lower Amazon Valley) Monasa rikeri (extralimital). 6 



dd. Malar apex white. 

 €. Whole head and neck (except white capistrum) black; remoges (except 

 inner secondaries) deep black, contrasting strongly with slate-gray of 

 wing-coverts. (Eastern Panama) Monasa fidelis (p. 397) . 



" For the present I do not attempt to discriminate between species and subspecies 

 in this genus, a very much larger amount of material being required for the proper 

 understanding of all the forms and their relationships. 



^Monasa morpheas (not Bucco morphoeus Hahn and Kuster) Allen, Bull. Essex 

 InBt.,viii, 1876, 80 (Santarem, Lower Amazon); Riker and Chapman, Auk, viii, 1891, 

 158 (Santarem). — Monasa riheri Ridgway, Proc. Biol. Soc. Wash., xxv, May 4, 1912, 

 88 (Diamantina, Lower Amazon; coll. U. S. Nat. Mub.). 



