AVES LARID.-E. 



217 



Clupeilarus verreauxi, Bp. Compt. Rend, xliii. p. 770 (1856: Chile). 

 Larus vociferus, Burm. La Plata Reis. II. p. 518 (1861 : Buenos Ayres: 



Montevideo) ; C. Burm. An. Mus. Nac. Buenos Aires, III. part X. p. 



248 (1888: Coast of Patagonia and Falkland Islands). 



FIG. 129. 

 ^ 

 GENERAL DESCRIPTION. 



Size. Adult male (breeding). Total 

 length, about 23 inches. 



Wing, 16.5 inches. 



Tail, 7.1 inches. 



Tarsus, 2.4 inches. 



Culmen, 2.25 inches. 



The female is appreciably smaller than the 

 male. 



Color. Adult male (breeding). General 

 color, white with a black or slaty black man- file of head. Bill from above. 



Larus dominicanus. Adult. Pro- 



From specimens procured by the 

 Princeton Expeditions. About ^ 

 natural size. 



tie and wings. 



Head : Entirely white. 



Neck: White. 



Back: Mantle and lower back slaty black. Rump and upper tail 

 coverts white. 



Wing: In general color like the mantle. Upper wing coverts slaty 

 black. The scapulars and all of the secondaries slaty black with broad 

 white tips, which together form a conspicuous alar bar. The primaries 

 are black, broadly tipped with white, and vary in decoration and amount 

 of white with the age of the individual as follows : Very mature birds 

 have the first primary white for about two inches apically, with only a 

 hair line of black next to the shaft. The second primary shows a white 

 mirror, subapically, which is most extensive on the inner web. Ordinary 

 adults have the white apical region of the first primary modified to a sub- 

 apical mirror; the second primary being decorated as in older birds. 

 Still younger adult birds have only the first primary decorated with a 

 white mirror, the second primary being black with a broad white tip like the 

 third. In all of these phases, the third primary is black with a broad white 

 tip. The fourth primary begins to show a greyish or white "wedge" on 

 the inner web. This increases in extent until on the seventh primary it 



