146 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
out a very narrow edging of blackish along the middle portion,* that 
of the second with a broader and more extended blackish edging. Ex- 
posed portion of middle and greater wing-coverts and outer web of 
tertials (except first), pure white, appearing as a continuous, unbroken, 
elongated patch on the closed wing; inner webs of tertials, blackish; 
secondaries, grayish-brown, the outer webs edged with white, but in- 
ner webs with no trace of white edging toward ends; primaries and 
their coverts, with alule, also grayish brown (or brownish gray) edged 
with white. Bill, uniform deep black; feet, duller black; “iris, dark 
brown.” Wing 3.70-3.80, tail, 3.80-4.20, culmen .50, tarsus .95, middle 
toe .58-.60.4 
Adult 2 in summer (Nos. 88987~8, Bering Island, May 11 and June 
10, 1882, L. Stejneger): Similar to the adult ¢, as described above, but 
nape, back, and scapulars, uniform plumbeous-gray, instead of black; — 
chin black, with (No. 88987) or without (No. 88988) a slight admixture 
of white. Wing 3.50-3.60, tail 3.85-3.90, culmen .45-.49, tarsus .90-.95, 
middle toe .55. 
[These two examples differ in slight details of coloration: No. 88988 
has the ‘‘mantle” absolutely uniform plumbeous-gray, while the other 
has a slight clouding of blackish on the scapular region. Another 
specimen from the same locality (No. 88985, obtained May 9) presumed 
to be a 2, though the sex is not marked, has still more black on the 
scapulars, while the hinder interscapulars are decidedly clouded with 
black. The measurements are, wing 3.75, tail 3.75, culmen .48, tarsus 
.90, middle toe .55. A specimen from Plover Bay, Siberia, obtained 
June 26, 1881, by Mr. E. W. Nelson, and marked ‘ ¢” (No. 89676), al- 
though in somewhat worn plumage, agrees minutely with No. 88988 in — 
coloration. It measures, wing 3.65, tail 3.90, culmen .50, tarsus .90, 
middle toe .55. 
Adult (?) in winter (No. 86259, La Paz, Lower California, January 9, 
1882+): Forehead, superciliary stripe, cheeks, chin, and throat white; — 
also side of neck and lower parts, except sides; jugulum with a large | 
crescentic patch of black, the posterior feathers narrowly tipped with | 
white; crown, occiput, and upper part of nape mixed black and ash- r 
gray, the latter predominating, or in fact almost uniform, centrally. In | 
other respects almost like the summer 2, as described above, but white — 
of wings and gray wash on sides somewhat tinged with brownish. Bill 
dusky, the mandible lighter brownish and paler basally. Wing 3.60, 
tail 3.85, culmen .42, tarsus .90, middle toe .50. 
*In No. 89146 there is no trace of dusky edging on the inner web of the outer pair, 
both rectrices being wholly pure white; even on the second pair the dusky edging is — 
very poorly defined, while the third feather, in addition to the pure white shaft, has — 
a broad, whitish streak on the middle portion of the inner web, while the correspond- — 
ing feather of the opposite side has no white at all! In No. 88986, however, the pat- 
tern is more symmetrical, though on one side the dark edging to the outer feather is 
perceptible only on the closest inspection. 
+The lesser measurements are represented by No. 89146. 
tCf. Proc. U.S. Nat. Mus., vol. 4, p. 414. 
