BIEDS OF NORTH AND MIDDLE AMERICA. 583 



ii. Legs and feet (in life) yellow; color of back, etc., paler 

 (intermediate between that of L. vegos and that of L. 

 argentatus). (Mediterranean, Black, and Caspian Seas and 

 • eastward to Lake iiaikal, south in winter to west coast of Af- 

 rica, Red Sea, India, etc.) Larus cachinnans(extraliniital).« 



hh. Mandible with a subterminal black spot; iris dark brown. (West- 

 ern North America, south in winter to western Mexico.) 



Lams calif ornicus (p. 620). 



bb. Depth of bill at gonydeal angle contained at least four and a half times in length 



of tarsus; middle toe, without claw, less than 45 mm.; mandible without 



any red. 



c. Bill with a subterminal band or transverse spot of black. (Northern North 



America, south in winter to Bermuda, Cuba, Gulf of Mexico, and southern 



Mexico.) Larus delawarensis (p. 623). 



cc. Bill without any black. 

 d. Gray "wedge''' on inner web of third primary (from outside) never tipped 

 with white nor carried definitely farther than tip of sixth (usually not 

 much beyond tip of seventh) primary; wing 339-380, averaging 363.4 

 in male; culmen 36.5-45, averaging 39.4 in male. (Northern Europe and 

 Asia, south in ^vinter to Mediterranean Sea, Nile basin, Persian Gulf, etc.; 



accidental in Labrador.) Larus canus (p. 627). 



dd. Gray "wedge" on inner web of third primary (from outside) always ter- 

 minated with white, this carried beyond tip of sixth (sometimes beyond 

 tip of fifth) primary; wing 328-366, averaging 358.9 in male, 344.6 in 

 female; culmen 32-38, averaging 36.4 in male, 34.1 in female. (North- 

 western North America, south in winter to southern California.) 



Larus brachyrhynchus (p. 632). 

 aa. Head and neek streaked or clouded, rump and upper tail coverts spotted or barred 

 with grayish brown or dusky, wing-coverts streaked or mottled with grayish 

 brown and whitisl; or pale buffy, and under parts more or less washed or clouded 

 with grayish brown. ( Young.) b 

 h. No "solid" black or dusky on tail, which is light brownish gray or grayish brown 

 (smoke gray or mouse gray), more or less mottled with whitish, 

 c. Darker, the back mouse gray, this color predominant over the lighter markings; 

 tail almost uniform mouse gray, the white mottlings few and confined almost 

 exclusively to the base and lateral feathers. 



Larus glaucescens, young (p. 597). 

 cc. Lighter, the back smoke gray, the whitish markings more numerous and 

 usually predominant; tail smoke gray, the white markings more numerous 

 and more generally dispersed. 



a Larus cachinnans Pallas, Zoogr. Rosso-Asiat. , ii, 1826, 318; Saunders, Cat. Birds 

 Brit. Mus., XX, 1896, 266. — Laroides cachinnans Bruch, Journ. fiir Om., 1855, 282. — 

 Larus te^copTjaeus Lichtenstein, Nomencl. Av. Mus. Berol., 1854, 99 (Arabia ;=no??ien 

 nudum); Dresser, Birds Europe, viii, 1873, 411, pi. 602, fig. 1. — Glaucus leucophaevs 

 Bruch, Journ. fur Orn., 1853, 101 (Red Sea). — Laroides leucophaeus Bonaparte, Nau- 

 mannia, 1854, 212. — Glaucus michahellesii Bruch, Journ. fiir Orn., 1853, 101 (Dalmatia). 

 Laroides michahellesii Bruch, Journ. fiir Orn., 1855, 282. — Larus michahellesii Erhard , 

 Faun. Cykladen, 1858, 45, 62. — Larus epargyrus Lichtenstein, Nomencl. Av. Mus. 

 Berol., 1854, 99.— (?) Larus heuglini Bree, Birds Europe, 2d ed., v, 1876, 58. 



b This key to the young has been prepared by Mr. J. H. Riley, at my request. — R. R. 



