WHITE-WINGED BLACK TERN. 9 



spotting and scribbling is very minute, and the underlying 

 grey spots are more distinct than in eggs of H. kiicoptera. 

 Axis, i*4-i'7 inch; diam., \'\-\2. 



III. THE WHITE-WINGED BLACK TERN. HYDROCHELIDON 

 LEUCOPTERA. 



Stenia leucoptera^ Meisner & Schinz, Vog. Schweiz, p. 264 



(1815); Seebohm, Hist. Brit. B. iii. p. 257 (1885). 

 HydrochcUdon hucoptera, Macgill. Brit. B. v. p. 661 (1852); 



Dresser, B. Eur. viii. p. 321, pis. 590, 591 (1875); 



B. O.U. List Brit. B. p 185 (1883); Saunders, cd. 



Yanell's Brit. B. iii. p. 552 (1884); id. Man. Brit. B. 



p. 619 (1889) ; Liiford, Col. Fig. Brit. B. part xxix. 



(1894); Saunders, Cat. B. Brit. Mus. xxv. p. 6 (1896). 



{Plate XCV.) 



Adult Male. — General colour above dark slate-colour ; head 

 and neck black, this colour overspreading the mantle ; lower 

 back, rump, upper tail-coverts, and tail pure white ; lesser 

 coverts round the bend of the wing white, the rest of the 

 wing-coverts pearly- grey, the innermost greater coverts rather 

 darker and more slaty-grey ; bastard-wing, primary-coverts, and 

 quills dusky, externally frosted with pearly-grey, the inner 

 primaries being almost entirely of this colour, the innermost 

 secondaries darker slate-grey ; entire under surface of bod)'', 

 from the chin to the vent, black, including the under wing- 

 coverts and axillaries ; vent, under tail-covcFts, and edge of 

 wing pure white ; " bill livid red ; feet orange red '\H. Saunders), 

 Total length, 9*0 inches; culmen, 0-95; wing, 8'o; tail, 2*7; 

 tarsus, 07. 



Adult Female. — Similar to the male in colour. Total length, 

 87 inches ; wing, ^•'Ty. 



Adult in Winter Plumage. — Differs from the summer plumage 

 in being pearly-grey above and white below, a collar round the 

 hind neck and forehead also white ; fore part of crown mottled 

 with black, which is much more apparent on the nape, and 

 forms a spot on the ear-coverts. 



