POLIOAETUS. 247 



feathers mesially shaded with a darker tint, many of the feathers of the 

 interscapular region, back, scapulars, and shoulders margined with white ; 

 primaries blackish brown, black at the tip past the notch, the inner web 

 becoming white on the margin toward tlie base, some showing remains 

 of brown bars; a few of the inner primaries, some of the adjacent second- 

 aries and wing-coverts, narrowly margined with huffy white; under sur- 

 face of the wings white, the outer series of the under coverts blotched with 

 brown ; feathers along the outer margin of the wing from elbow to base of 

 primaries, dark brown margined with white, under surface of the second- 

 aries and of the primaries past the notch ashy brown, the basal marginal 

 portion of the inner webs white, barred down the center portion with 

 brown; head, throat, and back of the neck white, a few feathers on the 

 nape having a streak of blackish brown down the center; lores blackish 

 lead-color; ear-coverts blackish brown, which color extends on to the sides 

 of the neck, where the feathers are brown margined with white; chest, 

 breast, and lower part of hind neck white, much mottled with brown 

 on the tips of the feathers, and occasionally centered with a blackish 

 stripe ; the remainder of the under surface, thighs, and tail-coverts white ; 

 tail above brown, feathers narrowly margined at the tips with white, the 

 inner webs of a lighter bro'WTi, all except the two center quills broadly 

 margined and toothed with white toward the base; under surface of tail 

 ashy white, tips of the feathers ashy margined with white. Bill black; 

 legs and feet lead-blue; iris yellow. Length, 760; wing, 508; tail, 228; 

 tarsus, 63 ; bill, 43 ;* from nostril, 30 ; culmen, 49. 



"Observation. — In some specimens, apparently fully adult, the whole of 

 breast, chest, and sides of the neck are strongly mottled with brown, and the 

 feathers centered with a blackish stripe ; the under wing-coverts are barred 

 with brown; the scapulars, upper wing-coverts, and quills scarcely if at 

 all margined with white ; in others the whole of the head and neck, except 

 the ear-coverts and sides of the neck immediately behind them, is white, 

 without any brown markings, and the dull brown of the chest takes no 

 definite form, but is for the most part darkest on the center of the 

 feathers." (North.) 



Genus POLIOAETUS Kaup, 1847. 



Bill decidedly compressed, width of upper mandible at nostril less than 

 its depth; primaries obliquely and slightly cut on inner web and exceed- 

 ing secondaries by less than tarsus; back of tarsus smooth with plate 

 divisions obsolete. 



* "The length of the bill varies considerably, some specimens, measured from the 

 antorior margin of the cere, being only 30, others 34." 



