1 52 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, is8a, 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. i58c. 



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. 



