SP. CHAR. _Adult male_ (51,343, Mazatlan, Mexico; Ferd. Bischoff. “Length, 16.00; extent, 38.00”). Above deep, rather dark cinereous, becoming paler and finer on the head above, where the feathers have the shafts (finely) black; wings with obsolete lighter bars; rump almost black. Upper tail-coverts immaculate pure white. Tail pure black, tipped with pale grayish-brown (this passing terminally into white); about 1½ inches from the tip is a continuous band of white, half an inch in width; and a little over an inch anterior to this is another narrower and less perfect one. Primaries approaching black at ends; the tips broadly edged with dull white, as also the ends of secondaries. Head uniform fine delicate ashy, becoming white on chin and throat, and approaching the same on the forehead; shafts of feathers on head above, and neck, black; neck with obsolete paler transverse bars, these most distinct on jugulum; the breast, abdomen, sides, flanks, axillars, and tibiæ are regularly barred transversely with cinereous and pure white, the bars of each about equal, the white, however, gradually increasing, and the ashy bars narrowing posteriorly, the tibiæ being finely barred; lower tail-coverts immaculate pure white. Lining of the wing white, with very sparse, faint, transverse zigzag bars next the axillars and on larger coverts; under surface of primaries white anterior to their emargination, beyond which they are more silvery, leaving about an inch of the terminal portion black, the end of each, however, ashy; outer two quills crossed by narrow bars of ashy, the rest with indications of the same, near the shaft. Fourth quill longest; third scarcely shorter; second shorter than fifth; first intermediate between eighth and ninth. Wing, 10.50; tail, 7.00; tarsus, 2.60; middle toe, 1.50. _Adult female_ (34,002, Mazatlan, June; Colonel Grayson). Cinereous above darker, the fasciæ of the wings hardly observable; front and throat scarcely whitish; rump almost pure black; second tail-band much broken and restricted. Ashy prevailing on the jugulum; ashy bars beneath rather broader. Wings, 11.00; tail, 7.50; tarsus, 2.80; middle toe, 1.70.