b NISUS RUFlTORyUES AND N. POLIOCEPHALUS. 



thau Nisus rufitorques aud presenting a difierent system of 

 coloration. 



The following measures are tal:en from eleven speci- 

 mens of our collection. 



Wing 63/e to 7'/e inches. Tail 5^2 to 6^/3 inches. 



As to the legs and toes , cere and eyes , it appears that 

 their color presents , instead of the more or less deep 

 yellow observed in those parts in Nisus rufitorques, a fine 

 reddish orange inclining sometimes, in the eye, even to 

 reddish brown. 



The system of coloration of the plumage may be stated as 

 follows. In the first plumage, the upper parts of the bird 

 are rufous , the lower parts of a yellowish white inter- 

 rupted , along the middle of each feather by a black streak , 

 a marking equally observed in the young of Nisus trino- 

 tatus, Buteo (Poliornis) poliogenys, Buteo (Bacha) rufi- 

 pectus , and , as an accidental characteristic in Haliaëtus vo- 

 cifer and HaUastur indus. The perfect plumage which is 

 produced by a change of color of the feathers and not 

 by moulting, shows the upper parts to be of a slaty gray, 

 passing on head and neck more or less to a whitish gray, 

 whereas the lower parts are of a pure white. The black 

 streaks of the under surface of the body , disaj^pear however 

 only gradually which is proved by specimens , in which their 

 number is considerably less or even reduced to a few. The 

 same is more or less the case with the black bars of the 

 primaries. 



JJ'oles irom ihe Leytlen IVIuseiiui. 



