102 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



of the bill is conspicuously different and strikingly distinctive; the 

 feet much weaker, with toes and claws more compressed. The 

 feathers of the underparts are much broader and with truncated 

 tips, and there are numerous other differences." (R. R.) 



KEY TO THE SPECIES AND SUBSPECIES OF CHONDROHIERAX 



a. Upper mandible pale yellowish white, inclining to bluish horn at base; feathers 

 of upperi)arts with concealed white bars on their bases (Cuba). 



C. wilsonii (p. Ill) 

 aa. Upper mandible black; no concealed white bars on feathers of upperparts. 

 h. Size larger; wing 265-301 mm. in males; 268-321 mm. in females. 

 c. Bill smaller; culmen from cere less than 45 mm, 



d. Plumage gray or dark gray, barred beneath with gray or dark gray and 

 white. 

 e. Ground color of underparts dark blackish plumbeous, white bars 

 wide (about 5 mm.) (central and eastern Mexico). 



C. u. aquilonis ad. d^ (p. 109) 

 ee. Ground color of underparts paler, deep plumbeous; white bars 

 narrow (1.5-3 mm.) (western Mexico to Argentina). 



C. u. uncinatus ad. d^ (p- 102) 

 dd. Plumage dark brown or blackish brown above, barred beneath with 

 brown on v.hite ground color or almost unbarred white. 



e. Underparts heavily barred C. u. iincinatusad. 9 (p. 102) 



C. u. aquilonis ad. 9 (P- 109) 

 ee. Underparts nearly unbarred white. C. u. uncinatus juv, (p. 104) 



C. u. aquilonis juv. (p. 109) 

 cc. Bill very large, culmen 50 mm.- C. u. immania ad. 9 " (extralimital) 

 66. Size smaller; wing 250 mm., in male; 262-266 mm. in females 



(Grenada) C, u. mirus (p. 110) 



CHONDROHIERAX UNCINATUS UNCINATUS (Temminck) 



Hook-billed Kite 



Adult male. —G-R AY phase: Above dark plumbeous, or plumbeous- 

 black, becoming fuscous, or fuscous-black, in worn plumage; the 

 occiput with much basal white and the upper tail coverts tipped and 

 banded with white; sizes of face, ear coverts, and chin deep to dark 

 plumbeous; under tail coverts white to ochraceous-bufi, uniform, or 

 with traces of grayish bars occasionally distinctly banded with plum- 

 beous. Remainder of underparts deep plumbeous (usually paler than 

 the upperparts) barred with narrow bands of white, buff, or cinnamon- 

 buff, which are variable in width, and are usually narrowly bordered by 

 fuscous or fuscous-black; axillaries and under wing coverts uniform 

 deep plumbeous, barred with white or buff: primaries banded (about 

 equally) with white and plumbeous-black below, dark plumbeous and 



" Chondrohierax tmcinatus inamanis Friedmann, Journ. Washington Acad, 

 Sci, xxiv, 1934, 315 (Ambata Oriente, Ecuador). 



