Bill depressed, wide at base, compressed to the end, nostrils basal; wing long, pointed, first primary usually longest, secondaries short; legs and feet short and weak; tail moderate, forked or emarginate. General form rather broad, robust; flight protracted, rapid. 1. Sub-genus Hirundo. Tail with the two external feathers disproportionately long; others graduated. 1. Hirundo rufa. Gmelin, Syst. Nat. I. p. 1018. (1788.) The Barn Swallow. Hirundo horreorum. Barton, Frag. Nat. Hist. of Penna. p. 17. (1799.) Hirundo americana. Wilson, Am. Orn. V. p. 34. (1812.) Hirundo erythrogaster. Boddaert, Tab. Pl. Enl. p. 45. (1783.)? Hirundo cyanopyrrha. Vieill., Nouv. Dict. XIV. p. 510. (1817.) “Hirundo rustica. Linn.” Aud. Orn. Biog. II. p. 413. Wilson, Am. Orn. V. pl. 38, fig. 1, 2; Aud., B. of Am. pl. 173, Oct. ed. I. pl. 48; Nat. Hist. N. Y. Birds, pl. 29, fig. 64; Buff., Pl. Enl. 724, fig. 1? Wings long; tail deeply forked with the two outer feathers much the longest; forehead, throat, and neck in front, chestnut, which color is separated from the paler color of the breast by a partial or rarely perfect collar of dark steel blue; entire upper parts steel blue, with a purple lustre, inclining to green on the wings and tail; breast, abdomen, and under tail coverts, chestnut, very pale in some specimens, but generally darker on the tail coverts; tail with a large spot of white on the inner web of every feather, except the middle two; bill and feet black; sexes very nearly alike. Dimensions. Total length, 7 inches; wing, 4½; tail, 3½. Female smaller. Hab. Throughout North America. Canada (Dr. Hall); Oregon (Dr. Townsend); Texas (Dr. Woodhouse); Santa Fé (Col. McCall); Indiana (Dr. Haymond); Long Island (Mr. Giraud); Cuba (Mr. Lembeye). This is one of the most abundant of the birds of the United States, and known to all classes and ages of the population. It is nearly related to the European House Swallow (_Hirundo rustica_), but can readily be distinguished on comparison. The European is rather the larger, the under-parts are darker, and the collar on the neck in front complete. In the present bird this collar is imperfect, with very rare exceptions. 2. Sub-genus Petrochelidon. Tail moderate or short, emarginate, but slightly forked. 2. Hirundo lunifrons. Say., Long’s Exp. to the Rocky Mts. II. p. 47. (1823.) The Cliff Swallow. Hirundo opifex. Clinton, Ann. N. Y. Lyceum I. p. 161. (1824.) Hirundo respublicana. Aud., Ann. N. Y. Lyc., I. p. 164. (1824.) “Hirundo fulva. Vieill.” Aud., Orn. Biog. V. p. 415, and Clinton, as above. Bonap., Am. Orn., 1. pl. 7, fig. 1; Aud., B. of Am., pl. 68, Oct. ed. I. pl. 47; Nat. Hist. N. Y. Birds, pl. 30, fig. 64.