LARUS. 35 



rump, upper tail-coverts, and tail, uniform pure white, more or less rose- 

 tinted in breeding season ; mantle some shade of gray.) 

 6 1 . Tarsus much longer than middle toe, with claw. 



Summer adult : Head sooty slate-color; mantle plumbeous-slate; five 

 outer primaries entirely black, or sometimes with a small terminal 

 spot of white ; rest of quills plumbeous, tipped with white, the sixth 

 sometimes with a subterminal black spot; bill and feet (in life) 

 dark brownish red. Winter adult : Head and neck white, the oc- 

 ciput and ear-coverts spotted or mottled with brownish gray, the 

 eyes more or less surrounded by the same ; otherwise as in summer. 

 Young : Head, neck, breast, and sides nearly uniform brownish gray, 

 darker on occiput and hind-neck, tinged with buff beneath ; mantle 

 grayish brown, the feathers broadly bordered with pale grayish buff; 

 centre of rump light brownish gray ; rest of rump, with upper tail- 

 coverts and posterior lower parts, white; basal half of tail light 

 gray, subterminal portion black, the tip narrowly white. Downy 

 young : Above grayish fulvous, varying to umber-brown, the head 

 irregularly striped or spotted, the back, wings, and rump marbled, 

 with dusky ; lower parts paler, the breast and belly more ochreous, 

 the fore-neck, sides, flanks, and ventral region faintly mottled with 

 darker. Length 15.00-17.00, wing 13.00, tail 5.00, culmen 1.75, tarsus 

 2.00, middle toe, with claw, 1.50. Eggs 2.18 X 1-55. Sab. Atlantic 

 coast of United States, south, in winter, through West Indies and 

 along both coasts of Middle America, and as far as the lower Ama- 

 zon 58. L. atricilla Linn. laughing Gull. 



b 2 . Tarsus not longer than middle toe, with claw. 



c 1 . Wing more than 10.00 ; culmen more than 1.00. 



d 1 . Bill brownish or reddish, its depth through the angle more than 

 one-fourth the culmen. Summer adult : Bill bright red (in life), 

 with more or less distinct darker subterminal band ; head deep 

 plumbeous-black, with a white spot on each eyelid ; mantle deep 

 plumbeous; quills bluish gray, the shafts white, all broadly 

 tipped with white, and the five outer ones marked with a sub- 

 terminal space of black; lower parts deeply tinted (in fresh 

 specimens) with rose-pink, and middle tail-feather tinged with 

 pearl-gray. Winter adult: Similar, but head white, the occi- 

 put, region round eyes, and ear-coverts, grayish dusky ; bill and 

 feet duller red. Young : Top and sides of head (except forehead 

 and lores), with back and scapulars, grayish brown, the longer 

 scapulars bordered terminally with pale grayish buff; quills 

 dusky (inner webs more plumbeous), tipped with white ; centre 

 of rump bluish gray ; rest of rump, with upper tail-coverts, 

 entire lower parts, forehead, lores, and eyelids, white. Length 

 13.50-15.00, wing 11.25, culmen 1.30, depth of bill at nostrils .35, 

 tarsus .60, middle toe, with claw, 1.60. Eggs 2.11 X 1.53. Sab. 



