154 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



Head, neck and entire under parts, pure white; rest of plumage, 

 glossy bluish black; wing, less than 19; primaries, dark slaty, show- 

 ing greenish tinge when held in the light ; two outer primaries, notched ; 

 tail, long and forked. Elanoides forficatus. 



Swallow-tailed Kite. 

 See No. 151. 



Wing, always over 18.50; belly and thighs, never white; only 

 adult birds have the hood and tail white. Haliceetus leucocephalus. 



Bald Eagle. 

 See No. 166. 



SECTION 3. Fourth primary, longest; tarsus, partly (not entirely) 



feathered. 



Tail, rufous brown (adult ) ; tail, whitish or grayish, with numer- 

 ous brown bars (immature). Buteo borealis, and races. 



Red-tailed Hawk. 

 See Nos. 158, i58a, is8b, 1580. 



General plumage, dark sooty brown, sometimes with pale under 

 parts, more or less streaked and spotted. Buteo borealis harlani. 



Harlan's Hawk. 

 See No. 1580. 



Wing, always over" 18.50; only adults have head and tail white. 



Haliceetus leucocephalus. 

 Bald Eagle. 

 See No. 166. 



SECTION 4. Fourth primary, longest; tarsus, entirely feathered. 



Thighs, tawny, more or less streaked or barred. 



Archibuteo lagopus sancti-johannis. 

 American Rough-legged Hawk. 

 See No. 164. 



General plumage, sooty brown or black (black plumage ) . > 



Archibuteo lagopus sancti-johannis. 

 American Rough-legged Hawk. 

 See No. 164. 



