Note 77 — Family FALCONIDÆ.—The Falcons. (continued 3)

Rostrhamus hamatus (Vieill.). Falco hamatus, Temm. Pl. Col. 61, 231, 1899.—Illig. Mus. Berol. Buteo hamatus, Vieill. Enc. Méth. III, 1223. Rostrhamus tæniurus, Cab. J. für. Orn. 1854, p. lxxx. No. 16,634 (Amazon River; Lieutenant Herndon). Entirely uniform plumbeous, with a glaucous cast, becoming darker on the head, and black on primaries and tail; tail perfectly even, with an obscurely indicated, narrow, interrupted band of dark plumbeous across its middle portion. A specimen in the collection of the Boston Society has the bands on the tail more conspicuous, and agrees with the R. tæniurus of Cabanis. I have seen no young specimens of this species, but, judging from Temminck’s figure, cited above, they are very similar to the same stage of R. sociabilis.