636 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



of feathers) of grayish white, the uniformly sooty median portions 

 of the feathers producing an effect of irregular dusky stripes, most 

 conspicuous on back and scapulars; the more anterior parts with 

 edges of feather more regularly barred, the mottling more profuse 

 on rump and upper tail-coverts, producing a more grayish appear- 

 ance; outer webs of wing-coverts variegated by whitish motthngs; 

 alulas and primary coverts with very indistinct bands of paler brown; 

 secondaries crossed by about nine bands (one terminal, three con- 

 cealed by greater coverts) of pale grayish brown, fading into paler 

 (sometimes whitish) on edges of outer webs; primaries crossed by 

 nine transverse series of quadrate spots of mottled pale brownish 

 gray, on outer webs, those beyond the emarginations indistinct, 

 except the terminal crescentic bar; proximal secondaries and middle 

 rectrices with coarse mottling or marbling of dusky brown or sooty 

 and grayish white, the markings usually with more or less of a tend- 

 ency to form irregular, broken bars; rest of tail dusky crossed by 

 about nine paler bands, these merely marked off by a narrow line or 

 edging of whitish or pale brownish gray mclosing a grayish brown, 

 sometimes shghtly mottled, space, though toward base of the rectrices 

 the mottling is more confused and the bands confused or broken up; 

 ground color of under parts grayish white, each feather of neck, chest, 

 breast, and abdomen with a broad, irregularly serrated, median stripe 

 of dusky brown or sooty; sides, flanks, anal region, and under tail- 

 coverts narrowly banded or barred with sooty brown and grayish 

 white, the legs with narrower, more irregular bars; ''eyebrows" (su- 

 percihary region), lores, and chin grayish white, with a dusky space 

 immediately in front of eye ; face grayish white with distinct concen- 

 tric semicircular bars of dusky brown; facial circle dark brown pass- 

 ing into white on f oreneck, where interrupted by a spot of brownish 

 black on throat; bill light dull yellow; iris lemon yellow. 



Dovm,y young. — Buffy white, the down on hindneck, back, scapu- 

 lars, and wings dark sooty brown basally, the tips pale dull buff or 

 pale brownish buffy. 



Adult male.— Lengili (skins), 575-625 (G06); wing, 410-447 (433); 

 tail, 300-323 (313.6); culmen, from cere, 23-26.5 (24.7).« 



Adult /emaZe.— Length (skins), 610-670 (636); wing, 430-465 

 (446); tail, 310-347 (323.3); culmen, from cere, 24.5-28.5 (26.1).^ 



Northern North America; breeding in Hudsonian and Upper 

 Canadian zones, from tree limit in Alaska and northwestern Macken- 



a Five Bpecimens. 



& Seven specimens. 



According to Ernest E. Thompson (Ernest Thompson Seton) a fully grown young 

 male specimen of this species weighed 26 ounces and had 480 square inches of mng 

 surface, or IS^^ square inches to each ounce of weight — nearly twice that of Cathartes 

 aura. The tail surface was 100 square inches. (Proc. U. S. Nat. Mus., xiii, 1890, 541.) 



