BIKDS OP INDIANA. 569 



V. FAMILY LARID^E. GULLS AND TERNS. 



a 1 Bill more or less hooked; general color chiefly white with a darker bluish-gray 

 or slaty mantle. Subfamily LARIN^E. GULLS. 



b 1 . Hind toe rudimentary or wanting, with minute claw or none. RISSA. 

 b 2 . Hind toe small, but with perfect claw. 



c 1 . Tail even. LARUS. 6 



c 2 . Tail forked. XEMA. 



a 2 . Bill not hooked, but narrow aird pointed, the mandibles even; tail (in our 

 species), deeply forked. Subfamily STERNIN^E. TERNS. 



d 1 . Tail much more than one-third length of wing, its outer feathers narrow 



and pointed; toes well webbed. 



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



GELOCHELIDON. 



e 2 . Bill slender, its depth at base not one-third its length. STERNA. 7 



d 2 . Tail little more than one-third wing; its outer feathers broad and 



rounded. HYDROCHELIDON. 8 



SUBFAMILY LARIN^E. GULLS. 

 6. GENUS LARUS LINNJETTS. 



Bill of a Gull much reduced. 

 a 1 . Length over 18. 



b 1 . Primaries without black; pearl-gray, fading gradually into white at tips. 

 c 1 . Wing over 16.50. L. glaucus Briinn. 9 



c 2 . Wing 16.50 or less. L. leucopterus Faber. 10 



b 2 . Primaries crossed with black ; shafts of primaries black in the black mark- 

 ings. 



d 1 . Length over 22. ; white tips of outer primary separated from the other 

 white by band of black. L. argentatus smithsonianus Coues. 11 

 d 2 . Length 20. or less. L. delawarensis Ord. 12 



a 2 . Length under 16. 



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

 e 2 . Bill black; feet red or yellow; wing under 11. 



L. Philadelphia (Ord). 14 



9. (42.) Larus glaucus BRUNN. 



Glaucous Gull. 

 Synonym, BURGOMASTER. 



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

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



