of the two colors varying with the individual. Wing, 14.40–17.00; tail, 8.00–9.50; culmen, .80–.95; tarsus, 2.30–2.70; middle toe, 1.50–1.70. Weight 1½–3½ lbs. _Hab._ Western Province of North America, from the Mississippi Valley, and the region of the Great Lakes (Michigan, Wisconsin, Iowa, to Arkansas, also Canada and Massachusetts) to the Pacific … var. _swainsoni_. Wing, 12.00–15.30; tail, 6.50–9.00; culmen, .85–.90; tarsus, 1.95–2.60; middle toe, 1.50–1.60. Colors similar, but the young paler than that of var. _swainsoni_. Adult unknown. _Hab._ Middle and South America, and southern border of the western United States, from New Mexico to Buenos Ayres (two specimens, Costa Rica, and Buenos Ayres, Mus. S. I.) … var. _oxypterus_. =B.= Four outer primaries with their inner webs cut. _a._ Form light, the legs slender; tail of adult without a subterminal band of black more distinct than the others. 3. =B. zonocercus.= Wing, 15.50–17.40; tail, 8.50–10.75; culmen, .90; tarsus, 2.50–2.80; middle toe, 1.60–1.85. Entirely deep black, with more or less concealed pure white spotting. _Adult._ Tail carbonaceous-black, with three very broad zones, of pure white on inner webs and ash on the outer webs. _Young._ Tail dark brown, the inner webs more or less, sometimes entirely, white, crossed by numerous oblique bands of black. _Hab._ Mexico (chiefly western?) and adjacent southwestern portions of the United States (Arizona, COUES; Southern California, San Diego, COOPER). 4. =B. lineatus.= Wing, 11.25–14.25; tail, 8.00–10.00; culmen, .75–.90; tarsus, 2.70–3.25; middle toe, 1.30–1.50. Fourth to fifth quill longest; first shorter than seventh. Outer webs of the primaries with quadrate spots of whitish; lesser wing-coverts dark rufous; lower parts rufous more or less barred with whitish, or whitish spotted longitudinally with dusky. _Adult._ Head, neck, lesser wing-coverts, and lower parts deep rufous, the lower parts more or less barred posteriorly with whitish. Primaries and tail black; the former with quadrate spots of pure white on the outer webs, and the latter crossed by six narrow bands of pure white, and tipped with the same. _Young._ Head, neck, and lower parts whitish, usually more or less tinged with ochraceous, and with longitudinal markings of dusky. Primaries and tail dusky; the former mostly ochraceous anterior to the sinuation of their outer webs, the latter crossed by numerous narrow bands of pale grayish-brown, these becoming paler and more ochraceous toward the base. Lesser wing-coverts more or less tinged with dark rufous.