646 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
or dusky, the tip, narrowly, whitish; outermost primary with outer 
web and a stripe on inner web next to shaft, together with terminal 
portion, black, the remaining portion white; second and third pri- 
maries (from outside) similar, but the white more and more restricted; 
fourth primary grayish white on both webs, the subterminal portion 
black for more than 25 mm.), the tip white; remaining (proximal 
primaries pale neutral gray; bill dusky; legs and feet pale brownish 
(in dried skins). 
Immature (young in first winter ?).—Similar to winter adults but 
central lesser wing-coverts dusky, tail with a subterminal band of 
dusky, and primaries as in first plumage. 
Adult male-—Wing, 257-273 (266.2); tail, 99-109.5 (103.8); ex- 
posed culmen, 28-33 (31.2); tarsus, 32-36 (33.8); middle toe, 28-32 
(80.3) .% 
Adult female.—Wing, 247-274 (259.7); tail, 97-108 (101); exposed 
culmen, 28.5-32 (30.1); tarsus, 33-35.5 (34); middle toe, 28.5-32 
(80.5).° 
Breeding in Alaska (Fort Yukon; Nulato), Yukon (upper Pelly 
River), northern Mackenzie (vicinity of Fort Anderson), and in 
extreme northwestern corner of British Columbia (Atlin); ¢ migrating 
southward over practically the whole of North America to extreme 
southern United States and northern Mexico (La Paz, etc., Lower 
California; Mazatlan, Sinaloa, March, Dec.; La Barca and Gua- 
dalajara, Jalisco; Guanajuato; Gulf of Progreso, Yucatan); wintering 
northward to South Carolina (more rarely to Long Island or even, 
very rarely, to Maine) and southern Washington; casual or accidental 
in Bermudas (Jan. 27 and Dec. 15, 1849, and Jan., 1876), western 
Peru (Tambo Valley), Hawaiian Islands (Poli-hula Lake, Kauai, 
Mar. 15, 1891), and in western Europe (England, Scotland, Cornwall, 
Ireland, and Helgoland). 
Sterna philadelphia Orv, in Guthrie’s Geography, 2d Am. ed., ii, 1815, 319 (near 
Philadelphia, Pennsylvania). 
Chroicocephalus philadelphia Lawrence, in Baird, Rep. Pacific R. R. Surv., 
ix, 1858, 852; Mem. Bost. Soc. N. H., ii, 1874, 317 (Mazatlan, Sinaloa, Mar. 27, 
1868).—Barrp, Cat. N. Am. Birds, 1859, no. 670.—Coorer and SucKELEY, 
Rep. Pacific R. R. Surv., xii, pt. ii, 1860, 276 (Puget Sound, Washington, 
resident).—Covss, Proc.-Ac. Nat. Sci. Phila., 1861, 247 (Gulf of St. Lawrence; 
habits); 1862, 310 (monogr.); Check List, 2d ed., 1882, no. 788.—BLAKISTON, 
Tbis, 1862, 10 (Hudson Bay, Aug. 12).—Datt and Bannister, Trans. Chicago 
Ac. Sci., i, 1869, 305 (Fort Yukon, Sitka, etc., Alaska).—Newrton, Proc. 
Zool. Soc. Lond., 1871, 57, pl. 4, fig. 6 (egg).—AtLEN, Bull. Mus. Comp. 
@ Nine specimens. 
6 Ten specimens, 
¢ Professor Cooke (Distribution and Migration of North American Gulls and their 
Allies, 1915, 57, 58) discredits alleged breeding records for other localities, among 
them places in southern British Columbia, Alberta, Manitoba, southern Keewatin, 
North Dakota, Minnesota, and Michigan. 
