Mr. Gould remarks that “this species has all the characters of a true _Buteo_, and will rank as one of the finest of this well defined group. In size it rather exceeds the Common Buzzard of Europe, which in its general style of colouring it somewhat resembles.” SUB-FAM.—FALCONINA, VIG. FALCO FEMORALIS. _Temm._ Falco femoralis, _Temm._ Pl. Col. 121 male; and 343 adult male. —— _Spix_, Av. Sp. Nov. 1. p. 18. This specimen was shot in a small valley on the plains of Patagonia, at Port Desire, in Lat. 47° 44′. It builds its nest in low bushes, and the female was sitting on the eggs in the beginning of January. Egg, 1·8 of an inch in longer diameter, and 1·4 in shorter; surface rough with white projecting points; colour nearly uniform dirty “wood brown,” thickly freckled with rather a darker tint; general appearance, as if it had been rubbed in brown mud. M. D’Orbigny supposed that Latitude 34° was the southern limit of this species; we now find its range three hundred and thirty miles further southward. The same author states that this falcon prefers a dry open country with scattered bushes, which answers to the character of the valleys, in the plains near Port Desire. TINNUNCULUS SPARVERIUS. _Vieill._ Falco sparverius, _Linn. et Auct._ I obtained specimens both from North and South Patagonia (Rio Negro and Santa Cruz), and Captain King found it at Port Famine in Tierra del Fuego. I saw it at Lima in Peru; and Mr. Macleay (Zoological Journal, vol. iii.) sent specimens from Cuba. According to Wilson it is common in the United States, and Richardson says its northern range is about 54°. The _Tinnunculus_ therefore, ranges throughout both Americas over more than 107 degrees of latitude, or 6420 geographical miles. It is the only bird, which I saw in South America, that hovered over one particular spot, in the same stationary manner, as the common English kestrel (_Falco tinnunculus_, Linn.) is so frequently observed to do. SUB-FAM.—CIRCINÆ. 1. CIRCUS MEGASPILUS. _Gould._ Circus megaspilus, _Gould_, in Proceedings of the Zoological Society, Part V. 1837, p. 10. _C. vertice corporeque supra intensè fuscis, lineâ stramineâ a naribus supra oculos ad occiput tendente; hoc rufescenti-fusco; primariis intensè fuscis ad basin cinereis, lineis nigris cancellatis; caudæ tectricibus albis; rectricibus intermediis cinereis, externis cinereo-stramineis, omnibus lineis latis fuscis transversim notatis, lineâ ultimâ latissimâ, apice sordidè stramineo; gulâ pectoreque stramineis, fusco variegatis; corpore subtus stramineo; plumis pectoris laterumque striâ centrali fuscâ notatis; rostro nigro; cerâ tarsisque flavis._ Long. tot. 22 unc.; _rostri_, 1½; _alæ_, 17; _caudæ_, 10½; _tarsi_, 3⅓.