_Young_ (♀, 48,826, Santiago, Chile, May, 1866; Dr. Philippi). Occiput and nape thickly marked with broad streaks of dusky, tinged with rusty; scapulars umber-brown, tipped with rusty; all the feathers of wings narrowly tipped with white; tail-feathers with a subterminal irregular bar of dark ashy; breast tinged with rufous, and with badly defined cuneate spots of deeper rusty. Wing, 12.25; tail, 7.50. (Perhaps not the youngest stage.) HAB. Tropical and warm temperate America (except the West Indies), from Chile and Buenos Ayres to Florida, South Carolina, Southern Illinois, and California; winter resident in latter State. Localities: Xalapa (SCL. 1857, 201); Guatemala (SCL. Ibis, I, 220); Brazil (PELZ. Orn. Bras. I, 6); Buenos Ayres (SCL. & SALV. 1869, 160); Venezuela (SCL. & SALV. 1869, 252). Specimens are from Santa Clara, California, Fort Arbuckle, Mirador and Orizaba, Mexico, Chile, and Buenos Ayres; from all points the same bird. This species presents a very close resemblance to the _E. melanopterus_ of Europe, and the most evident specific difference can only be detected by raising the wing, the under side of which is quite different in the two, there being in the European bird no trace whatever of the black patch so conspicuous in the American species. The primaries, also, on both webs are lighter ash, while the ash of the upper parts in general is darker than in _leucurus_ and invades more the head above, the forehead merely approaching white. The tail is more deeply emarginated, and the proportions of the primaries are quite different, the second being much longer than the third, and the first nearly as long as the second, far exceeding the third, instead of being about equal to the fourth. In the _melanopterus_, too, the black borders the eye all round, extending back in a short streak from the posterior angle, instead of being restricted to the anterior region and upper eyelid, as in _leucurus_. A specimen of “_E. axillaris_” from Australia (13,844, T. R. Peale) appears, except upon close examination, to be absolutely identical in all the minutiæ of coloration, and in the wing-formula, with _E. leucurus_; and differs only very slightly in the measurements of bill and feet, having these proportionally larger, as will be seen from the table. Another (32,577, H. Mactier Warfield) has the upper parts so pale as to be nearly white. A young specimen of _E. axillaris_ differs from that of _E. leucurus_ as follows: the occiput, nape, and dorsal region are stained or overlaid by dull ashy-rufous, instead of dark brownish-ashy; more blackish on the head. No other differences are appreciable.