15. LARUS. 



187 



black, with a narrow ring of white nearly enclosing the ej'e; lower 

 neck, tail, and under surface pure white ; mantle pearl-grey, the 

 secondaries scarcely edged with white; the 1st primary white, 

 except on the outer web and across the tip, where it is black ; the 

 2iid is black only across the tip and for a little way up the margin of 

 the inner web ; the 3rd and 4th with small white tips, broad black 

 subterminal bars, and much pearl-grey above on the inner webs ; 

 the remaining primaries grey, with subterminal bars up to the 7th, 

 where the bar is broken, while on the Sth there is merely a dark 

 margin to the inner web ; edge of the wing and the under-coverts 

 white : bill deep black ; iris dark brown ; tarsi and toes orange-red. 

 Total length 14 inches, culmen 1-5, wing 10"25, tail4'5, tarsus 1'4, 

 middle toe with claw 1-4. 



The sexes appear to be alike in size as well as in plumage. 



Adult in winter. Similar, but the head and nape white, 

 mottled with grey, especially on the auricular region ; tarsi and 

 toes duller in colour. 



Immature. Like the above, but mottled with brown on the upper 

 wing-coverts : brownish centres to the secondaries ; a brown sub- 

 terminal band on the rectrices ; blackish-brown bands on both sides 

 of the shafts in the three outer quills, and on the subterminal portions 

 of all the quills ; the extreme tips white to a small extent, but soon 

 abraded, except on the four uppermost : bill horn-brown. 



Younri (August 24th). Similar, but rather more dark colour in 

 the primaries next the shafts {see cut) ; crown brownish grey ; 



2 3 



Larus Philadelphia, jiiv. 



feathers of the upper neck and mantle tipped or barred with brown 

 and jiale buff, and the scapulars broadly edged with dull white. 



