50 EEPOET OF XEW JEESEY STATE MUSEUM. 



a. Upper mandible curved at tip, tail square. (Gulls) 



h. Size, large ; wing, 16.50-19.50. 

 c. Head and under parts white. 



d. Primaries without dark subterminal areas ; mantle very pale. 



Glaucous Gull, p. 51 

 dd. Primaries with dark subterminal spots and white tips, 

 e. Mantle dark slaty, almost black. 



Black-backed Gull, p. 52 

 ee. Mantle pearl gray. Herring Gull, p. 53 



cc. Head and under parts dusky. 



Young Herring and Black-backed Gulls, pp. 52-53 

 6&. Size, medium ; wing, 13.50-15.50. 



c. Hind toe absent, or only a rudiment. Kittiwake, p. 51 



cc. Hind toe present. 



d. Bill with a transverse black band. Ring-billed Gull, p. 54 

 dd. Bill entirely red. Laughing Gull, p. 55 



ddd. Bill dusky. 



e. Back uniform slate. Laughing Gull, p. 55 



ce. Back brown or mottled. 



f. Base of tail feathers white. 



Young Ring-billed Gull, p. 54 

 if. Base of tail feathers gray. 



Young Laughing Gull, p. 55 

 hhh. Size, small ; wing, 10.25. Bonaparte's Gull, p. 56 



aa. Upper mandible sharp pointed like the lower; tail forked. (Terns) 



&. Wing, 12.50-17.50. 



c. Tail less than half as long as the wing. Caspian Tern, p. 57 



cc. Tail more than half as long as the wing. 



d. Bill red or orange. Royal Tern, p. 57 



dd. Bill black, tipped with yellow. Cabot's Tern, p. 58 



hh. Wing, 9.25-12. 



c. Upper parts black, lower parts white. Sooty Tern, p. 63 



cc. Upper parts pearl, sometimes mottled with dusky, crown often 

 glossy black. 



d. Both webs of outer tail feathers white, 

 e. Under parts white. 



/. Outer web of outermost primary black. 



Roseate Tern, p. 60 

 ff. Outer web of outermost primary silvery gray. 



Gull-billed Tern, p. 56 

 ee. Under parts pearl, head white. Trudeau's Tern, p. 58 

 dd. Only one web of outer tail feathers white. 



e. Outer web white. Forster's Tern, p. 59 



ee. Inner web white. 



f. Dark band on inner web of outer primary deep black 



and .20 in. wide. Common Tern, p. 61 



//. Dark band on inner web of outer primary duller and 



only .12 in. wide. Arctic Tern, p. 59 



lU. Wing, 6-8.25. 



c. Tail white. Least Tern, p. 62 



cc. Tail slaty gray. Black Tern, p. 64 



