AVES. 
161 
Polyborus vulgaris. — The Caracara Eagle. 
Plate XXXVIII. fig-. 1. 
Upper parts blackish-brown; head black; feathers capable 
of being elevated to a crest; neck, breast, and shoulders, brown¬ 
ish-gray, with transverse wavy bars of darker brown ; tail white, 
with undulated dusky bands, and a broad black band at its tip ; 
beak blue at the base, horny-colour at the tip; iris hazel; cere 
and cheeks dull red; legs yellow; claws black. Twenty-one 
inches long. Inhabits Brazil. 
Genus 6.—HARPYIA.— Cuvier. 
Generic Character. —Beak much incurved; upper mandible 
very thick at the base, and continues straight for more than a 
third of its length, from whence it suddenly curves downwards, 
and is much arched towards the point, which is extremely sharp ; 
lower mandible, straight, short, and obtuse ; nostrils transverse 
and ovate; wings very short, reaching only to the middle of 
the tail; tail rounded at its extremity; legs partially feathered 
on their upper part; toes and talons very strong. 
Harpyia destructor .— The Great Harpy. 
Plate XXXVIII. fig. 2. 
Head slate-gray; back part furnished with a crest of long, 
broad, black feathers, margined with gray, increasing in length 
to the middle line of the head; fore part of the neck with a 
black collar; back and wings black ; under parts pure white ; 
tail white, crossed by transverse black bands, with the four al¬ 
ternating; ash-coloured or whitish spaces ; tip light ash-colour; 
beak arid claws black; legs dull yellow, and very robust. 
Length from the beak to the tail three feet and a half. Inhabits 
South America. 
Genus 7. — AQUILA.— Brisson. 
Generic Character —Head much flattened above, which, with 
the neck, is plumed ; eyes deeply sunk; beak thick, powerful, 
and straight at its base ; somewhat angular above, and strongly 
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