WHITE-WINGED BLACK TERN. 
9 
spotting and scribbling is very minute, and the underlying 
grey spots are more distinct than in eggs of H. leucoptera. 
Axis, I '4-1 7 inch; diam., I'l-i’a. 
III. THE WHITE-WINGED BLACK TERN. HYDROCHELIDON 
LEUCOPTERA. 
Sterna leucoptera, Meisner & .Schinz, Vog. Schweiz, p. 264 
(1815); Seebohm, Hist. Brit. B. iii. p. 257 (1885). 
Hydrochelidon leucoptera, 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, ed. 
Yarrell’s Brit. B. iii. p. 552 (1884); id. Man. Brit. B. 
p. 619 (1889) ; Lilford, 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 body, 
from the chin to the vent, black, including the under wing- 
coverts and axillaries ; vent, under tail-coverts, and edge of 
wing pure white ; “ bill livid red ; feet orange red "{H. Sa 7 inders). 
Total length, g'o inches; culmen, o‘95; wing, 8’o; tail, 27; 
tarsus, 07. 
Adult Female. — Similar to the male in colour. Total length, 
87 inches ; wing, 8-3. 
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. 
