214 



PATAGONIAN EXPEDITIONS: ZOOLOGY. 



pale, pearly grey. 



Fig. 128. 



The two middle tail feathers are immaculate white, as 

 are the two outer ones on each side. 

 The rest have subterminal areas of 

 dusky brown. The feet and legs are 

 pale brownish flesh color. The bill 

 dull flesh color, darkening at the 

 tip. The lower parts are pure white. 

 This bird is in fresh unworn feather 

 of singularly fine texture. I am 

 obliged to Mr. Howard Saunders, of 



London, for confirming my identification of these two specimens of Larus 



glaucodcs. 



Geographical Range. — Straits of Magellan, Southern Patagonia, Tierra 

 del Fuego, the Falkland Islands, and north on the Atlantic Coast to about 

 9° South Latitude. On the Pacific Coast north to about Coquimbo. 



Lams glaucodcs. Female. Immature P 

 U. O. C. 7910. About y^ natural size. 



In view of the several diagnoses given it should not be difficult to 

 identify this Gull in its many phases. However, Mr. Saunders writes : 

 "It must be admitted that there is often considerable difficulty in dis- 

 tinguishing between the young of this species and of L. maciilipeunis. 

 The easiest test is the larger proportion of white in the former, especially 

 on the third quill, in which the black of the innner web is quite detached 

 from the shaft ; whereas in young L. niacitlipeiuiis the black reaches the 

 shaft till the bird is a year older. As already stated, the latter species is 

 a trifle the larger." From Cat. Bds. Brit. Mus. XXV. p. 206 (1896). 



The naturalists of the Princeton Expeditions to Patagonia, procured the 

 two specimens described in detail above, and presumably saw many of 

 these Gulls. For other phases of plumage the material in the British 

 Museum of Natural History has been used as a basis for the above 

 descriptions. 



The two representatives of L. glaucodcs, secured by the Princeton Uni- 

 versity Expeditions to Patagonia, are here cited : 



