SP. CHAR. _Adult_ (♂, 51,689, Yukon, mouth of Porcupine River; Strachan Jones). Whole upper surface with numerous transverse bands of brownish-plumbeous and ashy-white. Anteriorly the light bars are about half the width of the dark ones; posteriorly they gradually increase, the bands of the two colors being about of equal width on the upper tail-coverts and tail; with the increase of the lighter bars, they become more ashy, and, correspondingly, the darker ones are more plumbeous; on the rump there is but little contrast between the bands of the two, causing a prevalent bluish cast. The bands are everywhere continuous, the light ones being interrupted only by the black shaft; there are generally on the anterior portions about three light bars on each feather, the last always terminal. Tail tipped with white, and crossed with equal continuous bands of hoary-plumbeous and ashy-white; the latter eleven in number, and finely sprinkled with deeper ash. Primaries brownish-plumbeous, plain past the middle portion, but on the anterior half with quadrate spots of creamy white on the outer web. Head above brownish-plumbeous, this prevailing; but along the median line the feathers are edged with buffy white; forehead dull white, this continuing back in a streaked superciliary stripe to the occiput; cheeks very thinly marked with fine streaks of dusky, this prevailing along the upper border of the ear-coverts; a deeper dusky suffusion beneath the anterior angle of the eye. Lower surface pure white; chin and throat, only, immaculate; jugulum with very sparse, narrow longitudinal streaks of blackish; sides with scattered cordate or nearly circular spots, these larger and transverse on the flanks and tibiæ; abdomen with scattered minute elliptical spots; lower tail-coverts with minute irregular sagittate or transverse spots of dusky. Under surface of the wing white; each feather of the lining with a medial tear-shaped streak of dusky; primaries crossed with narrow bars of dusky, fifteen in number on the longest. Wing-formula, 2–3–4–1–5. Wing, 13.50; tail, 8.60; culmen, .90; tarsus, 2.15; middle toe, 1.87. ♀ (43,139, Fort Anderson, May 24, 1864, “♀ and two eggs”; R. MacFarlane). Generally similar to the male. Head above conspicuously streaked, but the dusky prevailing. Above the transverse bands are less regular and continuous, anteriorly the plumbeous largely prevailing; posterior portions, however, as in the male, but on the rump the bands are more distinct. Beneath, the markings are more numerous, larger, and broader; those on the jugulum linear; those of the abdomen medially elliptical; laterally they are transversely cordate, and on the flanks in form of broad transverse spots, or broad bars; on the tibiæ and lower tail-coverts they form regular transverse bars,—on the latter, quite distant. Wing-formula, 2–3–4, 1. Wing, 15.50; tail, 9.50; tarsus, 2.15 and .80; middle toe, 1.95.