150 BIRDS. 



2. LARUS, Linnaeus. GULLS. 

 * Primaries without any black. 



1. L. glaucus, Briinn. GLAUCOUS GULL. ICE GULL. 

 BURGOMASTER. Bill yellow with red spot on lower 

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

 winter. 



2. L. leucopterus, Faber. WHITE -WINGED 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. 

 COFFIN-CARRIER. SADDLE-BACK. Mantle blackish slate 

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

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



4. L. argeniatus, Briinn. HERRING GULL. COMMON 

 GULL. Mantle grayish blue; large, 22 to 27 ; W. 18 or 

 less; 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. 15. N. Am., abundant. 



3. RISSA, Leach. KITTIWAKES. 



1. R. iridactyla, (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. IVORY GULLS. 

 1. P. eburnea, (Gm.) Kau-p. IVORY GULLS. Adults 

 pure white; young spotted; L. 16 to 20; W. 12. North- 

 ern, rarely to U. S. in winter. 



5. CHRtECOCEPHALUS, Eyton. ROSY GULLS. 

 1. C. atricilla, (L.) Lawr. BLACK -HEADED OR LAUGH- 

 ING GULL. Tarsus longer than middle toe and clawj 



