550 BIRDS—LARID. 
Larus tridactylus, WHEATON, Food of Birds, etc., Ohio Agric. Rep. for 1874, 575 ; Reprint, 
1875, 15. 
Larus tridactylus, LINNZUS, Fa. Suec., 55. 
Rissa tridaciyla, BONAPARTE, List, 1828, 62. 
Larus (Rissa) tridaciylus, Couus, Birds N. W., 1874, 644. 
Hind toe only appearing as a minuie knob, its claw abortive. Mantle rather dark 
grayish-blue; first primary with the whole outer web, and the entire end for about two 
inches, black; next one, with the end black about as far, but outer web elsewhere 
light, and a white speck at extreme tip; on the rest of the primaries that have black, 
this color decreases in extent proportionally to the shortening of the quills, so that the 
base of the black on allis in the same line when the wings are closed (a pattern peculiar 
to the species of Rissa) ; and these all have white apex. Bill yellow, usually clouded 
with olivaceous; feet dusky olivaceous. Rather small; 16-18; wing, 12; bill,14-14; 
tarsus about the same; middle toe atid claw longer; tail usually slightly emarginate. 
In winter, nape and hind neck shaded with the color of the mantle. Young :-—Bill black ; 
a black bar on the tail, another across the neck behind; wings and tail variously 
patched with black; dark spots before and behind the eyes; quills mostly black. 
Habitat, Arciic regions of both hemispheres. South in winter on the Atlantic coast 
to the Middle States. 
Very rare or accidental winter visitor on Lake Erie. Mr, Winslow notes 
the occurrence of three specimens in Cleveland harbor many years since. 
This appears to be the only record in the interior, except that of Mr. Nel- 
son, who records one individual identified, but not captured, by Dr. Hoy, 
on Lake Michigan, in 1870. 
Sub-genus Chrecocephalus. Form less robust and bill more slender than in sub-genus 
Larus ; in the breeding season the white of under-paris rosy-tinted, and the head enveloped 
in a dark-colored hood. 
LARUS PHILADELPHIA (Ord) Coues. 
Bonaparte’s Gull. 
Larus bonapartii, AUDUDON, Orn. Biog., iv, 1838, 212; B. Am., vii, 1844, 131.—TREMBLY, 
Field Notes, i, 1861, 120. 
Larus capistriatus, KIRTLAND, Ohio Geolog. Surv., 1838, 166, 185. 
Choicocephalus philadelphia, WHSATON, Ohio Agric. Rep. for 1860, 371; Benne 1861, 13. 
Larus philadelphia, WaeATON, Food of Birds, etc., Ohio Agric. Rep. for 1874, 575; Re- 
print, 1875, 15.—-Lan@pDon, Cat. Birds of Cin., 1877, 18; Revised List, Journ. Cin. Soc. 
Nat. Hist., i, 1879, 186; Reprint, 20. 
Sterna philadelphia, ORD, Guthiie’s Geog., il, 1815, 319. 
Larus capistratus, BONAPARTE, Am. Orn., iv, — 
Larus bonaparici, RICHARDSON, F'n. Bor-Am., ii, 1831, 425. 
Chroicocephalus philadelphia, LAWRENCE, Birds N. Am., 1858, 852. 
Larus philadelphia, GRAY, List Br. Birds, 1863, 235. 
Larus (Chreecocephalus) philadelphia, Cours, Birds N. W., 1874, 655. 
Tarsus about equal to middle toe and claw. Small; 12-14; wing, 94-104; tarsus, 14; 
bill, 14-14, very slender, like a Tern’s. Adult in summer:—Bill black ; mantle pearly 
