BiBDS OP Indiana. 569 



V. Family LARIDiE. Gulls and Terns. 



a' Bill more or less hooked; general color chiefly white with a darker bluish-giay 

 or slaty mantle. Subfamily Larin^e. (jULLs. 



b^. Hind toe rudimentary or wanting, with minute claw or none. RissA. 

 b^. Hind toe small, but with perfect claw. 



c^. Tail even. Larus. 6 



c2. Tail forked. Xema. 



o^. Bill not hooked, but narrow and pointed, the mandibles even; tail (in our 

 species), deeply forked. Subfamily Sternin,?;. Terns. 



(U. Tail much more than one-third length of wing, itsouter feathers narrow 

 and pointed; toes well webVjed. 

 e'. Bill stout, its depth at base etjual to one-third length of culmen. 



Gelochelidon. 

 e^. Bill slender, its depth at base not one-third its length. Sterna. 7 

 d'^. Tail little more than one-third wing; its outer feathers broad and 

 rounded. Hydrochelidon. 8 



Subfamily LARINJi;. Gulls. 

 6. Genus LARUS Linn^us. 



Bill of a (iull much reduced. 

 a^. Length over 18. 

 6*. Primaries without black; pearl-gray, fading gradually into white at tips. 

 «'. Wing over 16.50. L. glaucus Briinn. 9 



c^. Wing 16.50 or less. L. leucopterus Faber. 10 



b^. Primaries crossed with black; shafts of primaries black in the black mark- 

 ings. 



d'. Length over 22. ; white tips of outer i)riiTiary separated from the other 

 white by band of black. L. arg-entatus smithsonianus Coues. 11 

 cP. Length 20. or less. L. delawarensis Ord. 12 



a-. Length under 16. 



e'. Bill and feet reddish ; wing over 11. L. franklinii Sw. &. Rich. 13 

 '•'■', Bill black; feet red or yellow; wing under 11. 



L. Philadelphia (Ord). 14 



9. (42.) Larus glaucus Brunn. 



Glaucous Gull. 



Synonym, IUirgomaster. 



Adult. — "Plumage, pure white, except the mantle, which is grayish- 

 blue; bill, gamboge yellow, with a carmine patch toward the end of 



