131 
Genus GERANOAETLJS, Kaup 
Geranoaetus Kaup, Class. Siiug. V6g. 1844, 122. Type, Spizaetus melanoleucus Vieiee. 
Geranaetus Agass. 
Hetcroactus Kaup, 1845. — Contr. Orn. 1850, 74. — Sunp. Disp. Acc. Hemeroliarp. 1874,27. 
Hcteradus Kaup, Isis, 1847 (fide Suudevall). — Keichenb. 1850. 
i 
Ch.—F orm intermediate between that of Butco and Haliaetus. Wings 
very long, the primaries rigid, and tail very short and graduated. Bill 
much as in Haliaetus , the culmen being arched above the horizontal, but 
slightly convex, upper outline of the cere, the superior tomium doubly 
sinuated, and the tip well produced and sharp. Nostril obliquely hori¬ 
zontal. Feet typically buteouine; tarsus, about one and a fourth 
times the middle toe ; outer toe much longer than the inner; posterior 
toe much shorter than the inner. Tarsus with the anterior and pos¬ 
terior series of transverse scutelhe very continuous and perfect; web 
between the outer and middle toes well developed. Wing large and 
pointed; third or fourth quill longest; first shorter than seventh ; 
outer five with their inner webs deeply emarginated. Tail less than 
half the wing, graduated, the feathers very rigid. Feathers of the 
head and neck cuneate, approaching lanceolate; tibial plumes well 
developed; secondaries, 17. 
Somewhat intermediate between Butco and Haliaetus , this genus is 
nevertheless very distinct from either. It is, perhaps, most like the 
latter, with which it agrees in short, graduated tail, with rigid feathers, 
deep emargination of the five outer primaries, general form ot the bill, 
and lanceolate form of the feathers of the head and neck. The feet, 
however, are much more like those of Buteo , there being a well-developed 
web between the outer and middle toes, of which not a trace is seen in 
Haliaetus , while the scutellation is also that of the typical Buteones. 
But one species is at present known. 
GERANOAETUS MELANOLEUCUS. 
Spizaetus melanoleucus Veill. N. D. xxxii, 1819,57. 
Haliaetus melanoleucus D’Ojrb. & Laer. Syn. Av. 1838, 3.— D’Orb. Voy. Am. 
Merid. Ois. 1847, 76.— Burm. Th. Bras, ii, 1855,54.— Gray, Hand List, i, 1869,17. 
Pontoaetus melanoleucus Gray, Gen. i, 1845, 18. 
Cuncuma melanoleucus Gray, List Acc. B. M. 1848, 25. 
Geranoaetus melanoleucus Strickl. Orn. Syn. i, 1855, 55.— Burm. Kcise La Plata 
St. ii, 1861, 425.— Peez. Orn. Nov. 1865,7 (Chile) ; Orn. Bras. 1871, 49, 397.— 
Orton, Am. Nat. 1871, 624 (Quito Valley).— Hudson, P. Z. S. 1872, 534 (Rio 
Negro, Patag.).— Lee, Ibis, 1873, 131, 136 (Arg. Rep.).— Sce. <Sc Salv. Ibis, 1869, 
284 (Cape Negro, Str. Magellan, Nov. 29); P. Z. S. 1869, 155 (Tungasuca, Peru) ; 
Nom. Neotr. 1873, 119.— Rigw. Pr. Boston Soc. N. H. May, 1873, 68.— Sce. & 
Salv. Nom. Neotr. 1873, 119. • 
Aslnrina melanoleuca Sche. Mus. P.-B. Asturime, 1862, 5 ; Rev. Acc. 1873, 102. 
Butco melanoleucus Sharpe, Cat. Acc. B. M. 1874, 168. 
Spizaetus fusccscens Vieiee. N. D. xxxii, 1819, 55. 
Falco aguia Temm. PI. Col. i, 1824, pi. 302. 
Haliaetus aguia Cuv. Reg. An. i, 1829, 327.— Less. Tr. 1831, 42. 
Geranoaelus aguia Kaup, Contr. Orn. 1850, 74 .—Bonap. Consp. i, 1850, 15. 
Butco aguia Caban. & Tscnuci, Arch. f. Naturg. 1844, 264; Fauna Per. 1844, 89.— 
Send. Av. Tent. 1873, 107. 
Heteroaetus aguia Kaup, Contr. Orn. 1850, 74. 
Aquila obscura. y blanca Azara, Pax. Par. i, 1802, 61. 
Aquila parda Azara, l. c. 65. 
Hab ._Mountainous districts of Western and Southern South America, 
from Patagonia northward to New Granada and Southern Brazil. 
