388 
ICHNOSCELIS. 
slightly hooked, the sides much compressed, the lateral margins slightly sinuated; 
the nostrils lateral, placed in the fore part of the cere, large, and more or less 
rounded. Wings long , pointed, with the fourth quill the longest. Tail lengthened, 
broad and rounded at the end. Tarsi about the length of the middle toe , feathered 
below the knee, covered with large irregular scales in front and with small ones 
behind and on the sides. Toes lengthened, strongly scaled above, the inner stronger 
and shorter than the outer and all armed with long curved claws. The lores, 
sides of the head and throat denuded of feathers. — 3 Specc. 
a I tier ic a h us Gray, Genera Birds I. Append. 9. — Schlegel, Mus. Pays-Bas 
Polybori 9. [Guiana. Brasilia. 
Petit Aigle d'Amérique Buffon, Pl. enlum. 417. 
Falco americanus Boddaert, Tabl. PJ. enlum. 417. 
Falco aquilinus Gmelin, Syst. Nat. I. 286. 
Falco formosus Latham, Ind. Ornith. II. 138. $ <j> 
Falco nudicollis Daudin, Traité Ornith. II. 79. $ 
Ibycter leucogäster Vieillot, Galerie Oiseaux I. 20. Tb. 16. 
Gymnops aquilinus S Pix, Aves Brasil. I. 11. 
Ibycter aquilinus Gray, Genera Birds I. 9. 
Milvago nudicollis Burmeister, syst. Uebers. Th. Bras II. 37. 
Ibycter formosus v. Pelzeln, Wiener Zool. bot. Verhdlgn. 1862. XII. 135. 
aquilinus Gray, Genera Birds I. 9. — Ibycter americanus Gray. 
ater Swainson, Classif. Birds II. 209. Fig. b. — Schlegel, Mus. Pays-Bas 
Polybori 7, [Guiana. Brasilia. 
Daptrius ater Vieillot, Galerie Oiseaux I. 19. Tb. 5. 
Falco aterrimus Temminck, PI. color. 37. 342. 
Ibycter fasciatus Gray, Genera Birds I. 9. 
Gymnops aterrimus, G. fasciatus Spix, Aves Brasil. I. 10. 11. Tb. 4. juv. 
Ibycter aterrimus Kaup, Oken's Isis 1847. 353. 
Milvago aterrimus Burmeister, syst. Uebers. Th. Bras. II. 39. 
Daptrius fasciatus Gray, Handl. Birds I. 5. 
aterrimus Kaup, Oken's Isis 1847. 353. === Ibycter ater Swains. 
australis Kaup, Oken's Isis 1847. 357. — Polyborus australis Less. 
chimachina Kaup, Oken's Isis 1847. 354. — Polyborus chimachina Vieill. 
chimango Kaup, Oken's Isis 1847. 356. = Polyborus chimango Vieill. 
fasciatus Gray, Genera Birds I. 9. = Ibycter ater S wains. 
formosus v. Pelzeln, Wien. Zool. bot. Verhdlgn. 1862. XII. 135. = Ibycter 
americanus Gray. 
gymnocephalus d'Orbigny, Synops. Avium 2; Voy. Amer, mérid. Ois. 50. — 
Bolivia. 
leucogäster Vieillot, Galerie Oiseaux Tb. 16. = Ibycter americanus Gray. 
leucopygus Schlegel, Mus. Pays-Bas Polybori 8. = Ibycter sociabilis Schleg. 
moutanus Kaup, Oken's Isis 1847. 354. — Polyborus megalopterus Schleg. 
sociabilis Schlegel, Mus. Pays-Bas Polybori 7. [America merid. centralis. 
Bostrhamus sociabilis d'Orbigny, Synops. Avium 3. — Cassin, Illustr. Birds 
Calif. 107. — Baird, Birds NAmerica 38. — Gundlach, Journ. Ornitb. 
1871. XIX. 362. 
Herpetotheres sociabilis Vieillot, Encycl. méth. 1248. 
Falco hamatus Illiger, Temm. Pl. color. 61. 231. — Pz. Wied, Beitr. Natg. 
Bras. III. 182. 
Buteo hamatus Vieillot, Encycl. méth. 1223. 
Cymindis leucopygus Spix, Aves Brasil. I. 7. Tb. 2. 
Cymindis hamatus de Lafresnaye, Magaz. Zool. 1834. IV. Ois. Tb. 20. 
Bostrhamus niger Lesson, Traité Ornith. 56. 
Bostrhamus hamatus Cabanis, Schomb. Reise. III. 746. 
Gavilan de estero sociabile Azara, Apuntam. I. 84. 
Gavilan caracolero. 
ICHNOSCELIS Gray, 1849. = Ischnoscelis Strickl. 
