LARID.-E — THE GULLS AND TERNS — LARUS. 209 



Genus LARUS, Linn^us. 



Lams, Linn. S. N. ed. 10, L 1758, 136 ; cd. 12, L 1766, 224 (no particular type indicated). 



Leucus, Kaup, Nat. Syst. Eur. Tliicrw. 1829, 86 ("includes L. marinus, (jlaucus, and/(«CMs"). 



Laroidcs, Bi;khm, Vug. Deutschl. 1831, 738 ("includes most of the European hoodless Gulls"). 



Gavina, Bonap. Naum. 1854, 212 (" For L. canus and allies and for L. adouini." — Saunders). 



Chroicocephalus, Eyton, Brit. B. 1836, 53 (type, Lams capistratus, Tkmm. ?). 



Atricilla, Bonap. Nauru. 1854, 212 (type, A. Catesbai, Bp. ^ Larus atricilla, Linn.). 



Dominicanus, BpvUCII, t. c. 100 (type, Lo,rus marinus, Linn.). 



Glaiicus, Bkuch, J. f. 0. 1853, 101 (type. Lams (jlaucus, Linn.). 



Blastpus, " Bp." Buucii, J. f. 0. 1853, 108 (type. Lams modestus, TsCHUDi). 



Melagavia, Bonap. Naum. 1854, 213 (type, Larus Franklini, S\v. & Rich.). 



Char. Size exceedingly variable, ranging from that of the smaller Albatrosses down to that 

 of the medium-sized Terns; tail even; tarsus always longer than the middle toe with its claw 

 (except in L. minutus), and smoothish behind ; colors extremely variable, but young always 

 widely different from the adult. 



The genus Larus, in the comprehensive sense in which we have here, for reasons stated on 

 p. 196, adopted it, includes many very dissimilar forms, which probably represent distinct genera. 

 The North American species may be defined as follows : — 



At Adult with the entire head, neck, lower parts, and tail pure white. (Larus, LiNN.) 

 a. Mantle very pale pearl-blue ; primaries the same, fading into white toward the ends. 



1. L. glaucus. Wing, 16.75-18.60 inches; culmen, 2.15-2.65 ; depth of bill through the 



angle, .75-1.00 ; tarsus, 2.30-3.00; middle toe, 1.95-2.50. Eyelids in summer adult, 

 reddish pui'ple ; feet flesh-color. Hah. Circumpolar Regions, south, in winter, to Long 

 Island, the Great Lakes, and North Pacific. 



2. L. leucopterus. Wing, 15.40-16.50 inches ; culmen, 1.65-1.90; depth of bill through 



angle, .60-.70 ; tarsus, 2.05-2.20 ; middle toe, 1.70-1.95. Eyelids in summer adult, flesh- 

 color ; feet inclining to orange-red. Hah. Same as L. (jlaucus. 

 h. Mantle pale pearl-ldue ; primaries similar, but abruptly tipped with Avhite. 



3. L. Kumlieui. Five outer primaries marked with slate-gray spaces immediately before 



the white tips ; color of the mantle as in L. leucopterus, and size about the same. Eyelids 

 in summer adult reddish purple, or purplish flesh-color ; feet flesh-color. Wing, 15.00- 

 17.00 inches ; culmen, 1.60-1.90 ; depth of bill through angle, .55-66 ; tarsus, 2.10-2.40. 

 Hah. North Atlantic coast, breeding in Cumberland Sound, and migrating south in winter 

 to Nova Scotia, New Brunswick, and New York. 



4. L. Nelsoni Similar in plumage to L. Kumlicni, but much larger. Wing, 18 25 inches ; 



culmen, 2.35 ; depth of bill through angle, .80 ; tarsus, 3.05 ; middle toe, 2.40. Hah. 

 Norton Sound, Alaska. 



5. L. glaucescens. Five outer primaries without slate-gray spaces before the Avhite tips. 



Wing, 16.25-17.30 inches ; culmen, 2.20-2.60; depth of bill, .80-.90 ; tarsus, 2.35-2.90; 

 middle toe, 2.05-2.45. Hah. North Pacific coast of North America, south to Washington 

 Territory ; Cumberland Gulf. 

 c. Mantle dark slate, dark plumbeous, or blackish ; primaries similar, marked at and near the 

 ends with white. 



6. L. marinus. Mantle dark slate, or blackish slate, without blue shade. Wing, 17.60- 



19.50 inches ; culmen, 2.40-2.60 ; depth of bill through angle, .98-1.05 ; tarsus, 2.70- 

 3.10 ; middle toe, 2.10-2.50. Hah. Coasts of the North Atlantic ; in America, south to 

 Long Island and Great Lakes. 



7. L. schistisagus. Mantle deep dark plumbeous, or dark bluish slate. Eyelids in sum- 



mer adults, reddish violet-gray ; iris light yellow ; feet pinkish flesh-color. Wing, 18.10 

 inches; culmen, 2.35 ; depth of bill through angle, .90 ; tarsus, 2.75 ; middle toe, 2.40. 

 Hah. North Pacific, chiefly on the Asiatic side, but also occasionally along the coast of 

 Alaska (Port Clarence ; Bean) . 

 VOL. II. — 27 



