Haliaëtus chimachima, _Less._ 2. Milvago pezoporos, _nob._ Aquila pezopora, _Meyen._ 3. Milvago chimango, _n._ Polyborus chimango, _Vieill._ Haliaëtus chimango, _Less._ Those which have a buteo-like appearance, and with rather short and stout tarsi, are, 5. Milvago leucurus, _n._ Falco leucurus, _Forster’s_ Drawings No. 34. Falco Novæ Zealandiæ, _Gm._ —— Australis, _Lath._ Circaëtus antarcticus, _Less._ Falco Australis, _Jard. & Selby’s III. Orn._ n. s. pl. 24. 6. Milvago albogularis, _n._ Polyborus (Phalcobænus ?) albogularis, _Gould._ 7. Milvago montanus, _n._ Phalcobænus montanus, _D’Orb._ 8. Milvago megalopterus, _n._ Aquila megaloptera, _Meyen._ 1. MILVAGO PEZOPOROS. Aquila pezopora, _Meyen._ Nov. Act. Phys. Med. Acad. Cæs. Leo. Car. Nat. Cur. suppl. 1834. p. 62. pl. VI. I obtained two specimens of this bird, one from Port Desire, in Patagonia, and another at the extreme southern point of Tierra del Fuego. Meyen[7] describes it as common on the plains of Chile, and on the mountains to an elevation of 4000 or 5000 feet. As M. D’Orbigny does not notice this species, I presume it is not found on the Atlantic side of the continent, so far north as the Rio Negro, where he resided for some time. The habits and general appearance of _M. chimango_ and this bird are so entirely similar, that I did not perceive that the species were different; hence I cannot speak with certainty of their range, but it would appear probable that the _M. pezoporus_ replaces in Chile, Tierra del Fuego and Southern Patagonia the _M. chimango_ of La Plata. In the same manner the _M. chimango_ is replaced between the latitudes of Buenos Ayres and Corrientes by a third closely allied species, the _M. ochrocephalus_. D’Orbigny, (p. 614, in the Zoological part of his work) speaking of the Chimango, says, “Il n’est pas étonnant qu’on ait long-temps confondu cette espèce avec le _falco degener_, Illiger, (the _M. ochrocephalus_) et qu’on l’ait cru de sa famille. Il est impossible de présenter plus de rapports de forme et surtout de couleur. Nous les avions, nous-même confondus au premier abord; mais, en remarquant, ultérieurement, que le sujet que nous regardions comme le mâle ne se trouvait qu’à Corrientes, tandis qu’il y avait seulement des femelles sur les rives de la Plata, l’étude plus attentive des mœurs de ces oiseaux, et les localités respectives qu’habite chacun d’eux, ne tarda pas à nous y faire reconnaître, avec Azara, deux espèces vraiment trèsdistinctes; mais qui, depuis, ont encore été confondues, sous la même nom, par M. la Prince Maximilien de Neuwied.[8]” I may observe that the figure given in Meyen’s work, has the iris coloured bright red, instead of which it should have been brown. 2. MILVAGO CHIMANGO.