264 FALCONID.E 



flexor longus hallucis supplies the hallux, sending a slip to the 

 second toe ; as a rule the two tendons are connected by a vinculum ; 

 oil gland tufted ; ambiens and femoro- caudal muscles present ; outer 

 toe not reversible ; after-shafts present, head covered with feathers. 



Authorities are in marked disagreement in regard to the division 

 of this family into subfamilies ; I have, therefore, here not attempted 

 to separate the genera into larger divisions. 



Key of the Genera. 



Edge of the upper mandible with a distinct 

 tooth behind the hook. 



a. Head not crested, no long feathers on the 



flanks. 

 a 1 . Nostrils rounded with a central bony 



tubercle. 



a 2 . Tarsus distinctly shorter than the 

 middle toe and claw, inner and outer 



toes equal Falco, p. 266. 



fe 2 . Tarsus equal to or longer than the 

 middle toe and claw, outer toe 



longer than the inner Tinnunculus, p. 275. 



6 1 . Nostrils oval without bony tubercle ; 



tarsus 1 times length of the middle toe Poliohierax, p. 288. 



b. Head crested; flank feathers elongated 



covering the abdomen and thighs Baza, p. 286. 



B. Edge of the upper mandible straight or 



slightly sinuated, not toothed. 

 a. Tibia and tarsus practically equal in length, 

 the difference between them always, 

 less than the hind claw. 

 a 1 . Lores and sides of the face bare ; tarsus 



covered with polygonal scales Polyboroides, p. 379. 



6 1 . Lores and sides of the face covered 



with feathers and bristles. 

 a?. Nostrils circular with a central bonj T 



tubercle MeUerax, p. 360. 



b 2 . Nostrils oval without bony tubercle. 

 a 3 . Tarsus with transverse shields in 

 front and smaller polygonal ones 



behind Circus, p. 366. 



b 3 . Tarsus with transverse shields in 

 front and behind, with a few 

 smaller polygonal ones at the 

 sides. 



