456 CHECK-LIST OF NORTH AMERICAN BIRDS. 



Subgenus LARUS Linnaeus. 



Larus glaucescens Naumann. Glaucous-winged Gull. 



Larus glaucescens Naumann, Naturg. Vogel Deutschl., X, 1840, 351. 



Modern form reported from Pleistocene: Upper San Pedro, near San Pedro, 

 California. 



Larus argentatus Pontoppidan. Herring Gull. 



Larus argentatus Pontoppidan, Danske Atlas, I, 1763, 622. 

 Modern form reported from Pleistocene: Fossil Lake, Oregon. 



Larus oregonus Shufeldt.' 



Larus oregonus Shufeldt, Amer. Nat., XXV, No. 297, Sept., 1891, 820. 

 Pleistocene: Fossil Lake, Oregon. 



Larus pristinus Shufeldt. ^ 



Larus pristinus Shufeldt, Trans. Conn. Acad. Arts Sci., XIX, Feb., 1915, 

 54, pi. XIV, fig. 112. 



?01igocene (John Day) : Willow Creek, Oregon. 



Larus robiistus Shitfeldt.^ 



Larus robuslus Shufeldt, Amer. Nat., XXV, No. 297, Sept., 1891, 819. 

 Pleistocene: Fossil Lake, Oregon. 



Subgenus CHROICOCEPHALUS Eyton. 



Chroicocephalus Eyton, Hist. Rarer Brit. Birds, 1836, 57. Type, by subs, 

 desig., Larus capistratus Temminck = L. ridibundus Linnaeus (Gray, 

 1840). 



Larus Philadelphia (Ord). Bonaparte's Gull. 



Sterna Philadelphia Ord, in Githeie, Geog., 2d Amer. ed., 1815, 319. 

 Modern form reported from Pleistocene: Fossil Lake, Oregon. 



Genus XEMA Leach. 



Xetna Leach, in Ross, Voyage Discovery, 1819, App., Ivii. Type, by 

 monotypy, Larus sabini Sabine. 



1 Subgeneric allocation provisional. 



2 Generic assignation in original description tentative. 

 ^ Subgeneric allocation provisional. 



