FALCONIDJE — BUTEONINM : EAGLES. 553 



4th quill longest ; 1st shorter than 9th ; 4 primaries emarginated, and one sinuated, on inner 

 ■wehs ; 5 sinuated on outer wehs. Tail about | as long as wing, rounded. Outstretched feet 

 reaching beyond end of tail." (Ridgway.) One species. 

 629. d. gru'beri. (To F. Gruber.) Gruber's Buzzard. " Immature °i? General plumage dull 

 dark bistre, with a grayish-umber cast in some lights, darkest on the head above and back ; 

 the posterior lower parts paler and more reddish ; throat and neck much tinged with pale 

 rusty ; primaries uniform black. Tail like the rump, hnt with a more hoary tinge, not paler 

 at the tip, and crossed with 7 or 8 very naiTOW obscure bars of darker, the last of which is 

 distant an inch or more from the eud. Lining of wings dark bistre, much tinged with rusty, 

 this prevalent toward the edge ; under surfaces of primaries white anterior to their emargina- 

 tion, beyond which they are ashy, approaching black at the ends ; ashy portion with distant, 

 very obsolete, dusky bars, but the cheeks and throat streaked obsoletely with this color. No 

 distinct white anywhere about head or neck. Wing 10.00 ; tail 5.80 ; tarsus 2.70 ; middle toe 

 1.40." (Eidgway.) California'? A second specimen has been discovered since tlie description 

 here copied was made. " Closely alUed to, if not identical with, Urubitinga." (Sharpe.) 



185. THRASYAE'TUS. (Gr. ^pao-ur, *^asMS, bold ; aeToi, aetos, an eagle.) Harpy Eagles. A 

 genus containing one species of enormous size, the most powerful raptorial bird of America, if 

 not of the entire sub- order. Head with a broad flowing occipital crest. BiU of great length 

 and depth, much compressed, so hooked that the curve of the culmen is about a quadrant of a 

 circle, the commissure about straight, the tomia festooned but not toothed; cere extensive, with 

 nearly vertical fore-edge, close to which are the narrowly oval nostrils about inidway between 

 tomia and culmen; lores extensively naked and bristly; superciliary shield prominent; feet 

 and talons of immense strength ; tarsus feathered a little way down in front ; the covering of the 

 feet reticulate, excepting a few scales on top of the toes ; lateral toes much shorter than middle 

 one ; inner claw much larger than middle one ; hinder one much the largest of all. Wings 

 rather short, but very ample, the secondaries entirely covering the primaries when folded ; 

 wing as a whole much vaulted, the outer quills strongly bowed. Tail long, f the wing, fan- 

 shaped, vaulted. 



531. T. harpyi'a. (Gr. dpwvta, harpma, a harpy.) Harpy Eagle. The largest and finest speci- 

 men before me I judge to have been nearly or about 4 feet long ; the wing is about 2 feet ; the 

 tail 18 inches; chord of culmen, including cere, 2.75 inches ; depth of hill 1.50 ; tarsus over 

 4.00 ; chord of hind claw nearly 3.00. Head and entire under parts dull white, more or less 

 obscured with ashy or dusky, particularly on the crest, across the throat, and on the tibiae, 

 which latter are in some cases regularly barred with blackish. Upper parts at large ashy-gray, 

 intimately but irregularly barred with glossy black, especially on the wing-coverts. Flight- 

 feathers mostly blackish, but with more or less ashy nebulation, to which whitish variegation is 

 added on the inner webs. Tail pretty regularly barred with black and ash, in other cases 

 irregularly nebulated with light and dark ash. The bill appears to have been blackish, the 

 feet of some yellowish color. Young birds are much darker. C. and S. Am. and Mexico, a 

 well known and most formidable bird of prey, reaching the Texas border. 



186. A'QXJILA, (Lat. aquila, an eagle.) Golden Eagles. Birds of groat size, robust form and 

 powerful physique, but in technical characters near Buteo and especially Arehibuteo. Tibia 

 extensively flagged. Tarsus closely feathered all around to the toes ; toes mostly reticulate on 

 top, margined, outer and middle webbed at base. Bill large, long, very robust ; tomia lobed ; 

 nostrils oval, oblique ; superciliary shield prominent. Wings long, pointed by the 3d-5th quills, 

 2d subequal to 6th, 1st very short, 5 or 6 emarginate on inner webs ; 2d to 6th or 7th sinuate 

 on outer webs. Tail moderate, rounded or graduated. !Peathe.rs of occiput and nape lanceolate, 

 acute, discrete, like a raven's throat-plumes. Sexes alike ; changes of plumage not great. 

 This extensive genus includes the eagles properly so called, of which there are numerous Old 

 World species, but only one American. 



