BIRDS OF NORTH AND MIDDLE AMERICA 517 



third the length of wing; third, fourth, and fifth, or fourth, fifth, and 

 sixth, primaries longest, the first shorter than tenth; inner webs of 

 five outer primaries siauated; proximal secondaries large and broad, 

 extending to tip of eighth or ninth primary. Tail a little more than 

 two-thirds to nearly three-fourths as long as wing, distinctly rounded, 

 the rectrices relatively broad. Tarsus more than one-fourth as long 

 as wing, about two-fifths as long as tail, slender, the acrotarsium and 

 planta tarsi each with a single series of broad, transverse scutella 

 (those of the latter often fused), the extreme upper portion of the 

 acrotarsium feathered; middle to about two-fifths as long as tarsus or 

 slightly less; outer toe much smaller and shorter than inner toe, falling 

 slightly short of distal end of second phalanx of middle toe; the inner 

 extending to much beyond middle of thu^d phalanx of middle toe; 

 hallux much shorter than inner toe; claws moderate in size and 

 curvature, except that of outer toe, which is conspicuously smaller 

 than that of middle toe, that of the hallux about as long as the digit 

 (in G. n. nigra) or much shorter (in G. gracilis) ; ^^ web between basal 

 phalanges of outer and middle toes small but obvious. 



Plumage and coloration. — Plumage fuh, soft, and blended; loral 

 region rather sparsely feathered, the feathers with bristly shafts but 

 without the usual long bristlelike tips; remiges (especially proximal 

 secondaries) and rectrices relatively broad, the outer primaries 

 (especially the first) more or less bowed or incurved; plumage of thighs 

 very short. Adults mostly plain bluish gray, slate color or slate- 

 blackish, with two or tliree bands (more or less broad) of white, buffy, 

 or ochraceous across the otherwise black tail; underparts sometimes 

 more or less barred with white. Young not conspicuously different 

 from adults, but more variegated with white. 



Range. — Tropical continental America, from southern Mexico to 

 Argentina, Bolivia, and Peru. (Three species, with sLx races.) 



Type.~Gera7iospiza gracilis (Temminck) . 



KEY TO THE NORTH AND MIDDLE AMERICAN FORMS OF GERANOSPIZA 



a. Chin and throat largely white; rest of underparts with considerable white 

 flecking. 

 b. Dark areas on underparts slightly brownish deep neutral gray (Dari^n 



and western Ecuador) Q. nigra balzarensis, juv. (p. 522) 



bb. Dark areas on underparts darker — chaetura-black (east and central 



Mexico to Panama) .G. nigra nigra, juv. (p. 518) 



aa. Chin and throat dark, uniform like rest of underparts. 



b. Darker; general color of bird blackish with a faint slate bloom (eastern 

 and central Mexico to Panama). 

 c. Under tail coverts blackish with narrow whitish tips. 



G. nigra nigra, ad. (p. 518) 



" In G. gracilis, which is very distinct from G. caerulescens, the claws appear 

 to be much shorter, less strongly curved, and less acute. 



