152 Field Museum of Natural History — Zoology, Vol. IX. 



Two outer primaries, notched; primaries, dark slaty blue, show- 

 ing greenish tinge when held in the light; tail, long and forked; 

 under parts and thighs, white. " Elanoides forficatus. 



Swallow-tailed Kite. 



See No. 151. 



SECTION 4. Fourth primary, longest; four or five outer primaries, 

 emarginate, or notched; upper tail coverts, white. 



Upper tail coverts, white; under surface of tail, white or pale ru- 

 fous, with several bands of dark brown. Circus hudsonius. 



Marsh Hawk. 



See No. 154. 



SECTION 5. Fourth primary, longest; four or five outer primaries, 



emarginate, or notched; upper tail coverts, not white; tarsus, 



partly (but not entirely) feathered. 



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

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



Red-tailed Hawk. 

 See Nos. 158, 158a, is8b, 1580. 



General plumage, dark sooty brown, sometimes with under parts 

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



Harlan's Hawk. 

 See No. 1580. 



SECTION 6. Fourth primary, longest; four or five outer primaries, 



emarginate, or notched; tarsus, entirely feathered; upper tail 



coverts, not white. 



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. 



