552 BIRDS—LARID&. 
erable flocks ; in fall it is rather more regular, but in less numbers than 
in spring, single birds or pairs often lingering for several days about 
favorite feeding places. | 
Audubon first saw this bird when crossing the Ohio from Cincinnati to 
Newport, Kentucky, to view the nests of the Cliff Swallows, in 13819. 
GENUS XEMA. Leach. 
Like sub-genus Chrecocephalus. Tail forked. 
XEMA SABINEI (Sab.) Leach. 
Work-tailed Gull. 
Xema sabinit, WHEATON, Ohio Agric. Rep. for 1860, 371, 379; Reprint, 1861, 13, 21. 
Aema sabinei, WHEATON, Food of Birds, etc., Ohio Agric. Rep. for 1874, 575; Reprint, 
1675, 15.—RipGway, Ann. Lye. N. Y., x, 1874, 393. 
Larus sabinei, J. SABINE, Linn. Trans, xii, i818, 522. 
Xema sabinei, LEACH, App. Ross, Voy., 1825. 
Adult :— White, including inner primaries, most of secondaries, and greater coverts ; 
head enveloped in a slate-colored hood, succeeded by a velvety-black collar; mantle 
slaty-blue, extending quite to the tips of the tertiaries ; whole edge of the wing, and 
first five primaries black, their extreme tips, and the outer half of their inner webs to 
near the end, white; bill black, tipped with yellow; feet black; length, 13-14; wing, 
10-11; bill, 1; tarsas, 14; tail, 5, forked an inch or more. The changes of plumage are 
correspondent with those of L. philadelphia; in the young the tail is often simply emar- 
ginate. 
Habitat, Arctic regions of both hemispheres. Spitzbergen. In America, south in win- 
ter to New York, and Great Salt Lake, Utah. 
Accidental in winter on Lake Erie. Mr. Winslow informs me that he 
took an immature bird of this species in Cleveland harbor many years 
since. The specimen was preserved and mounted, and placed in the 
museum of Cleveland Medical College. He has since informed me that 
from lack of care it has been destroyed by vermin. Mr. Nelson killed a 
specimen in full breeding dress on Lake Michigan, near Chicago, in 
April, 1873, but unfortunately it was not secured. 
Subfamily StTERNIN®. Terns. 
Covering of bill continucus (no cere) hard and horny throughout; bill paragnathous, 
relatively longer and slenderer than in the Gulls, very acute, the commissure straight or 
nearly so to the end; nostrils generally linear. Tail never square, almost invariably 
forked (often deeply forficate). Wingsextremely long and pointed. Feetsmall and weak. 
Sub-genus Gelochelidon. Bill remarably short, stout and obtuse, hardly or not half as 
long again as the tarsus. 
STERNA ANGLICA Montague. 
Gull-biled Tern; Marsh Tern. 
Sterna aranea, KIRTLAND, Ohio Geolog. Surv., 1838, 166, 185.—Wumaton, Ohio Agric. 
Rep. for 1860, 371; Reprint, 1861, 13. 
