BIRDS OP NORTH AND MIDDLE AMERICA. 5 



/. Wing-tip mucli shorter and more rounded, the longest primaries exceed- 

 ing distal secondaries by only one-fourth the length of wing, the 

 ninth primary shorter than foui'th, the tenth (outermost) very much 

 shorter than distal secondaries; tail very little longer (sometimes 



shorter) than wing, slightly rounded Micrococcyx (extralimital).a 



ee. Wing more roimded, the ninth primary shorter than first; tail nearly one 



and a half times to twice as long as wing. 



/. Bill relatively much shorter, deeper, and more strongly deciirved, its 



depth at anterior end of nostrils about equal to half the distance from 



nostril to tip of maxilla, the exposed culmen not longer (usually 



shorter) than tarsus and deciu-ved from near base. 



g. Tail only one and a half times as long as wing, or slightly less; tenth 



(outermost) primary decidedly less than half as long as the longest; 



small (wing less than 110 mm.) Coccycua (p. 42). 



gg. Tail more than one and a half times as long as wing; tenth primary 



not less than half as long as the longest; large (wing 134-197 mm.). 



h. Tail much more than one and a half times as long as wing, graduated 



for much more than one-third (sometimes for one-half) its length; 



bill and feet relatively smaller; upper parts rufescent (the pileum 



sometimes gray), tliroat rufescent or vinaceous, under parts of 



body gray or dusky Piaya (p. 45). 



hh. Tail little more than one and a half times as long as wing, graduated 

 for not more than one-thu-d its length; bill and feet relatively 

 larger; upper parts olive or slaty, the tail blackish; under parts 

 chestnut (one species with throat white shading into gray on 



chest) Hyetornis (p. 53). 



ff. Bill relatively much longer, more slender, and straighter, its depth at 

 anterior end of nostrils equal to less than one-thu-d (sometimes only 

 one-fourth) the distance from nostril to tip of maxilla, the exposed 

 culmen decidedly longer than tarsus and nearly straight to near tip 



of maxilla where rather abruptly deciu^ved Saurothera (p. 57). 



dd. Tarsus more than one-fourth as long as wing. 



e. Tarsus less than one-thu-d as long as wing; upper tail-coverts very long, 

 covering more than basal two-thirds of tail; bill very short, its length 

 from anterior end of nostril not greater than distance from same point 

 to anterior angle of eye; wing-tip rather long, the longest primaries 

 exceeding distal secondaries by more than one-fifth the length of 

 wing; seventh primary longest, the ninth much longer than third. 



Tapera (p. 66). 



ee. Tarsus more than one-third as long as wing; upper tail-coverts short or 



only moderately developed, covering not more (usually much less) than 



basal half of tail; bill longer, its length from anterior end of nostril much 



greater than distance from same point to anterior angle of eye; wing-tip 



very short, the longest primaries very little if any longer than distal 



secondaries; seventh primary shorter than the longest, the ninth shorter 



than first. 



/. Third to sixth primaries longest and longer than longest secondaries; 



nostril open, not distinctly operculate; mesorhinium broadly rounded 



or flattened; depth of bill at anterior end of nostril equal to less than 



half the distance from nostril to tip of maxilla. 



a Micrococcyx Ridgway, Proc. Biol. Soc. Wash., xxv, May 4, 1912, 99. (Type, 

 Coccyzus pumilus Strickland.) (MtKpoc, small; Kokku^, a cuckoo.) 

 South America. (Two species.) 



