This species, long known as a bird of South America, was first ascertained to be entitled to a place in the ornithological fauna of the United States by Mr. John G. Bell, of New York, who noticed it in California, and previously at Panama. We have since seen specimens from various parts of California, and suspect that it is abundant in that and probably in other countries of Western America. Though closely related to other South American species, the present bird may be distinguished very easily from the Purple Martin of the United States (_P. purpurea_), by the greater width and much greater length of the bill, and it is smaller in size. We are not confident that we have ever seen the perfectly plumaged adults of this bird, though the specimens above described were obtained by Mr. Bell in the spring, and have the general appearance of maturity, except that the lustre of the plumage is but faint. Little or nothing is known of its habits or history. III. GENUS COTYLE. Boie, Isis, 1822, p. 350. Bill small, weak, wide at base, compressed to the tip; wing long, pointed, first and second quills longest; secondaries short, truncate, and emarginate; tail moderate, wide, even or slightly emarginate; legs short, slender; toes rather long, slender; colors dull, usually fuliginous brown of various shades; size of American species smaller than those of either of the preceding genera. This genus contains about twelve species, inhabiting various regions of both continents, and all, so far as known, more or less terrestrial in their habits. In addition to those about to be described, there are three other American species restricted to the southern division of this continent. 1. Cotyle riparia. (Linn.) The Bank Swallow. The Sand Martin. Hirundo riparia. Linn., Syst. Nat. I. p. 344. (1766.) Hirundo cinerea. Vieill., Nouv. Dict. XIV. p. 526. Wilson, Am. Orn. V. pl. 38, fig. 4; Aud., B. of Am., pl. 385, Oct. ed. I. pl. 50; Nat. Hist. N. Y. Birds, pl. 28, fig. 62. Bill weak; wing long; first primary longest; tail emarginate; legs short; tarsus with a tuft of short downy feathers near the insertion of the hind toe; entire upper parts and wide band across the breast light fuliginous or grayish brown; quills and tail brownish black; throat, abdomen and under tail coverts white; under wing coverts light fuliginous; bill and feet dark. Dimensions. Total length, 5 inches; wing, 4; tail, 2 inches. Female slightly smaller. Hab. The whole of North America. Oregon (Dr. Townsend); California (Mr. Bell); Indiana (Dr. Haymond); Cuba (Mr. Lembeye); Indian Territory, New Mexico (Dr. Woodhouse); Florida (Mr. William Bartram).