150 BIRDS. 



2. LARUS, Linnaeus. Gulls. 

 * Primaries without any black. 



1. L. glaucus, Brunn. GLAucotrs Gull. Ice Gull. 

 BuEGOMASTBK. Bill yellow with red spot on lower 

 mandible; large; L. 30; W. 18. Arctic regions; S. in 

 winter. 



3. L. leucopierus, Faber. White - Wikged Gull. 

 Similar but smaller; L. 23; W. 17. Same region. 

 ** Primaries crossed with black (adult), or all black (young). 



3. L. marinus, L. Great Black - Backed Gull. 

 Cofpin-Caeribe. Saddle- Back. Mantle blackish slate 

 color; largest of our Gulls; L. 30 or more; W. 18; feet 

 flesh colored. N. Atlantic, S. in winter. 



i. L. argentatus, Briinn. Herring Gull. Commok 

 Gull. Mantle grayish blue; large, 32 to 37 ; W. 18 or 

 Jess; feet flesh colored. N. Am., abundant. 



5. L delawarensis, Ord. Ring-Billed Gull. Plum- 

 age like preceding; feet olivaceous; webs yellow; bill 

 yellowish, a black band at the tip; size moderate; L. 

 20; W. 16. N. Am., abundant. 



3. RISSA, Leach. Kittiwakes. 

 1. R. tridaciyla, (L.) Bon. Kittiwake Gull. Mantle 

 dark grayish blue; hind claw a minute knob; L. 16 to 

 18; W. 12. Northern, U. S. in winter. 



3. PAGOPHILA, Kaup. Itort Gulls. 

 1. P. eburnea, (Gm.) Kaup. Ivory Gulls. Adults 

 pure white; young spotted; L. 16 to 30; W. 13. North- 

 ern, rarely to U. S. in winter. 



5. CHR(ECOCEPHALUS. Eyton. Rosy Gulls. 

 1. C. atrioilla, (L.) Lawr. Black - Headed oe Laugh- 

 ing Gull. Tarsus i longer than middle toe and claw; 



