_Adult._ Lower parts light rufous barred with white. _Young._ White prevailing on the lower parts. _Hab._ Eastern Province of the United States … var. _lineatus_. _Adult._ Lower parts deep dark rufous, almost free from bars, except posteriorly. _Young._ Dark spotting on the lower parts predominating. _Hab._ Pacific Province, and southern Western Province, of the United States … var. _elegans_. _b._ Form robust and heavy, the tarsus stout; tail of the adult with a subterminal band of black broader than the other. 5. =B. borealis.= Wing, 13.25–17.75; tail, 8.50–11.30; culmen, .90–1.15; tarsus, 2.70–3.40; middle toe, 1.60–1.95. Weight, 2½ to 4 lbs. Third to fifth quill longest; first shorter than seventh and shorter than tenth. Colors extremely variable, ranging from entirely pure white beneath, through various shades of ochraceous and rusty, and greater or less amount of darker spots and bars, to an entirely uniform brownish-black. _Adult._ Tail deep rufous, generally paler at the tip; with or without black bars. _Young._ Tail grayish-brown, crossed by nine or ten bands of black, much narrower than the gray ones. Lower parts always with white predominating. Tibiæ and lower tail-coverts without transverse bars, at any age. Lower parts with white always predominating. Tail never with more than one bar of black. Feathers of the head and neck edged laterally with rufous; scapulars and wing-coverts much variegated with whitish; upper tail-coverts white, barred with rufous. Throat with blended streaks of blackish, this usually predominating; tibiæ and lower tail-coverts plain yellowish-white. _Hab._ Eastern Province of North America, to the Missouri plains … var. _borealis_. Similar, but colors much paler, the lower parts entirely pure white, with little or no spotting on the abdomen. Tail usually destitute of the black subterminal band. _Hab._ Plains, from Texas to Minnesota … var. _krideri_. Similar to the last, but lower parts strongly tinged with rufous on the tibiæ, and upper parts much darker. Tail always destitute of the subterminal black band. _Young_ not distinguishable from that of var. _calurus_. _Hab._ Cape St. Lucas … var. _lucasanus_.