224 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



//. Size smaller; wings, cf not over 430 mm., usually under 440 mm., 

 not over 450 mm. 

 g. Size very small, wings under 400 mm. 



B. albicaudatus colonus, ad. (extralimital)" 

 gg. Size larger, wings over 400 mm. (Texas to Venezuela). 



h. Chin and middle of throat white like the breast and abdomen. 

 B. albicaudatus hypospodius. ad. (p. 232) 

 hh. Chin and whole throat dark gray, sharply demarcated from 

 the white breast. 



B. albicaudatus h3rpospodius, im. (p. 233) 

 ee. Underparts largely blackish or brownish black. 



/. Size larger; wings, cf 430 mm. or over, 9 440-475 mm. 



B. albicaudatus albicaudatus, juv. (extralimital) 

 //. Size smaller; wings, cf not over 430 mm., ? usually not over 450 

 mm., usually under 440 mm. 

 g. Size very small, wings under 400 mm. 



B. albicaudatus colonus, juv. (extralimital) 

 gg. Size larger; wings over 400 mm. (Texas to Venezuela). 



B. albicaudatus hypospodius. juv. (p. 233) 

 dd. Tail much less than half as long as wing, graduated; five outer primaries 

 with inner webs emarginated. 



subgenus Geranoaetus (extralimital) 

 e. Abdomen white, finely barred with dark gray. 



B. melanoleucus meridensis, ad, (extralimital)" 

 ee. Abdomen with much black (like breast). 



B. melanoleucus meridensis, juv. (extralimital) 



Subgenus Brewsteria Maynard 



Large Biiteones (wing about 400-478 mm.) resembling Butaetes but 

 differing in much broader bill and gape, the width of the latter at 

 rictus nearly equal to length of middle toe with claw; inner toe (with- 

 out claw) extending to much beyond base of third phalanx of middle 

 toe; middle toe only two-fifths as long as tarsus; lower portion (about 

 one-sixth) of acrotarsium and sides of tarsus unfeathered; culmen 

 (chord) as long as claw of hallux; tail less than half as long as wing, 

 unhanded (at least in adults), and first primary shorter than seventh. 



Bill relatively stout, very broad basally, its width at point where 

 anterior edge of cere reaches maxUlary tomium greater than length 

 of outer claw, the width of gape at rictus nearly equal to length of 

 middle toe with claw; culmen strongly and regularly curved from base, 

 the maxillary tomium less than half as long as corneous rhino theca; 



JO Buteo albicaudatus colonus Berlepsch, Journ. fiir Orn., xl, 1892, 91 (Island 

 of Curagao). — Tachyiriorchis albicaudatus exiguus Chapman, Bull. Amer. Mus. 

 Nat. Hist., xxxiv, 1915, 637 (Barrigon, head of Rfo Meta, Colombia). — Buteo 

 albicaudatus colonus Peters, Check-list Birds of World, i, 1931, 228. This race is 

 douV)tfully distinct from hypospodius. 



" Geranoaetus melanoleucus meridensis Swann, Synop. Accip., ed. 2, 1922, 

 68 (Nevada, 3,000 meters; M6rida, Venezuela); Peters, Check-list Birds of World, 

 i, 1931, 227. 



