POLIOAHTUS. 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 the 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 buffy 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 brown, 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 
anterior margin of the cere, being only 30, others 34.” 
