Obs. This very handsome Hawk is especially abundant in the Southern States. It cannot readily be confounded with any other North American species, though we have not been able to compare it with the _Elanoides yetapa_, Vieill., of South America, with which it is either identical or very similar. II. GENUS ELANUS. Savigny, Nat. Hist. Egypt, I., 97. (1809.) Bill short, compressed, hooked; wings long, pointed; tail moderate, generally emarginate; tarsi short. Contains four species only, much resembling each other; one of which is American, one African, and two Australian. 1. Elanus leucurus. (Vieill.) The Black-shouldered Hawk. The White-tailed Hawk. Milvus leucurus. Vieill., Nouv. Dict., XX. p. 563. (1818.) Falco dispar. Temm., Pl. Col., I. (Liv. 54, about 1824.) “Falco melanopterus. Daud.” Bonap., Jour. Acad. Philada., V. p. 28. “Falco dispar. Temm.” Aud., Orn. Biog., IV. p. 367. Bonap., Am. Orn., II. pl. 11, fig. 1; Temm., Pl. col. 319; Aud., B. of Am., pl. 352, oct. ed. I. pl. 16. Gay’s Chili Orn., pl. 2. Head above, entire under-parts, and tail, white, the middle-feathers of the latter usually tinged above with ashy, and the head posteriorly tinged with the same color, which gradually shades into a fine light-cinereous, which is the color of the upper-parts of the body, quills, and greater wing-coverts. Lesser wing-coverts glossy black, which forms a large oblong patch; inferior wing-coverts white, with a smaller black patch. Bill dark; tarsi and feet yellow. Dimensions. _Female_—total length, 15½ to 17 inches; wing, 12; tail, 7½ inches. _Male_—smaller. Hab. Southern States; California (Dr. Heermann); South Carolina (Prof. Gibbes); Chili (Lieut. Gillis). Spec. in Mus. Acad., Philada. Obs. An abundant species in the Southern and South-western States. It is larger than the African _E. melanopterus_, with which it has been confounded, but considerably resembling it and the Australian species in form and general characters. III. GENUS ICTINIA. Vieill., Analyse, p. 24. (1816.) NERTUS. Boie, Isis, 1828, p. 314. PŒCILOPTERYX. Kaup, Class., p. 112. (1844.) Bill short, tip emarginated; wings long, pointed; tail rather short; usually emarginated; tarsi short. Two American species constitute this genus. 1. Ictinia mississippiensis. (Wilson.) The Mississippi Kite. Falco mississippiensis. Wilson, Am. Orn., III. p. 80. (1811.) Falco ophiophagus. Vieill., Nouv. Dict., XI. p. 103. (1817.) “Ictinia plumbea. Gm.” Aud., Orn. Biog., II. p. 108. Vieill., Gal., I. pl. 17; Wilson, Am. Orn., III. pl. 25, fig. 1; Aud., B. of Am. pl. 117, oct. ed. I. pl. 17.