BIRDS OF NORTH AND MIDDLE AMERICA 545 



primaries sinuated (not emarginated) at about (on outermost web 



anterior to) middle portion of inner web Polyborinae (p. 578) 



cc. Hallux elongated (nearly as long as lateral toes) ; tarsi uniformly covered 

 with thin, roughly imbricated small scales; m.etasternum truncated, 

 entire, without notches or foramina; dorsal portion of spinal pteryla 

 enlarged on all sides, undivided, and sparsely feathered. 



Herpetotherinae (p. 548) 

 Nostril a large broadly oval or subpyriform opening without bony rim or 

 central tubercule; wing short (little if any longer, sometimes shorter, than 

 tail), much rounded (outermost primary shorter than innermost); posterior 

 margin of auricular region composed of differently fornaed, narrow, stiff, 

 recurved feathers, forming a sort of "facial ruff" (as in Striges and 

 buteonine genus Circus). (Dorsal pteryla essentially as in Herpetotherinae). 



Micrasturinae (p. 558) 



KEY TO THE NORTH AND MIDDLE AMERICAN GENERA AND SUBGENERA OF 



FALCONIDAE 



\. Nostril large, broadly oval or subpyriform, without bony rim or central tubercle; 

 wing short (little if any longer, sometimes shorter, than tail), much rounded 

 (outermost primary shorter than innermost) ; posterior part of auriculars 

 composed of narrow, stiff, recurved feathers, forming a sort of facial ruff. 



Micrastur (p. 559) 

 I. Nostril small, circular, or oblique— linear, with a bony margin and central 

 tubercle; wing long (always decidedly longer than tail), pointed or mod- 

 erately rounded (outermost primary never shortest, usually much longer 

 than innermost one); no facial ruff. 

 h. Hallux elongated (nearly as long as lateral toes) ; tarsi uniformly covered 



with thin, roughly imbricated, small scales Herpetotheres (p. 550) 



6&. Hallux abbreviated (much shorter than lateral toes); tarsi covered with 

 smooth, variously formed scales, the acrotarsium with a greater or lesser 

 number of transverse scutellae. 

 c. Maxillary tooth and mandibular notch indistinct or obsolete; three or more 

 outer primaries sinuated (not emarginated) at about middle portion of 

 inner web (much anterior to middle on outer web) . 

 d. Tarsus one-half to two-thirds its length longer than middle toe without 

 claw, the acrotarsium with a greater or lesser number of transverse 

 scutella; outer toe but little longer than inner toe; inner webs of 

 primaries deeply sinuated; habits more or less terrestrial, carnivorous, 

 and sarcophagous, 

 e. Nostril linear, obliquely vertical (the lower end anterior to the upper), 

 in upper anterior portion of cere, its tubercle concealed, the ante- 

 rior outline of cere vertical and nearly straight; bill deep and 

 compressed; occipital feathers elongated into a depressed crest. 



Polyborus (p. 595) 



ee. Nostril circular, in middle of cere, its central tubercle exposed ; anterior 



outline of cere obhque, doubly curved; bill much less deep, little 



compressed. 



f. Tomial tooth and notch nearly obsolete; malar region nearly if 



not quite naked, sometimes with the skin developed into a 



pendant wattle; outer toe not longer thanf inner toe; hallux 



much longer than basal phalanx of middle toe; claws slightly 



curved, very blunt ; planta tarsi without distinct rows of quadrate 



