FAMILY LAUID.E. (lULLS AND TERNS. 



39 



Section 2. Length, over 21; bill, over 2; underparts, 



not whtte. 



Outer webs of primaries, asli color (immature). 



Lnruit ijlnurnn. Glaucous Gull. 

 See No. 24. 



Outer webs of primaries, tlark l)rown; wing, over 17. .50; depth of 1)ill at angle, ovt-r .110 

 (immature). Larus marinus. Great Black-backed Gull. 



See No. 27. 



Outer webs of primaries, dark brown; deptli of bill at angle, under .90; wing, \indor 17. .50 

 (immature). Larus argentatns smithsoniamis. American Herring Gull. 



See No. 30. 



Section 3. Length, over 21 ; bill, under 2; underparts, white. 



Back, grayish bhie, more or less black on primaries. 



Laruy anipntatus smithsoninnus. American Herring Gull. 



See No. .30. 



Back, pale pearl color ; pri- 

 maries, whitish or pearl color, 

 shading to white at tips. 



Lams lenctipterus. 

 Iceland Gull. 

 See No. 2.5. 





/ 



A^ \ v.- ■. 



Great Blark backeil Gull. 



RiiiR-lnlleii Gull. 



Back, pale peai'l color: ])i'imari<'s 

 marked with slatj' gray. 



Larus kumJieni. Kumlien's Gull. 



See No. 2G. 



Herring: Gull. 



