254 SPOLIA ZEYLANICA. 
in mistake for H. hybrida. No authentic specimens appear 
to have been obtained. Found by rivers and tanks through- 
out India and Burma, but rarer in the south than in the north. 
Habits —Those of the last species. The only likely place 
in the Island for these two Terns is on the broad sandy reaches 
of the lower Mahaweli-ganga and in the adjoining marshes. 
STERNA FLUVIATILIS (Blanford, Vol. IV., p. 318; 
Legge, p. 1015). 
The Common Tern. 
Description Summer : A black cap from the forehead to 
the nape, extending down the side of the head to the lower 
edge of the eye ; back and wings ashy-gray. The first primary 
has the outer web black and the portion of the inner web 
next the quill blackish, the remainder of the inner web white ; 
the black decreases on the second and inner primaries. The 
rump, upper tail coverts, and the inner webs of the tail feathers 
are white ; the outer webs of the tail feathers gray. The lower 
lores, cheeks, chin, throat, wing lining, and under tail coverts 
are white or nearly white ; breast and abdomen pale vinous gray. 
In winter the forehead is white or mottled, and the crown 
streaked with black ; lower parts whitish. 
Immature birds have a whitish forehead, a sooty-black 
nape, a dirty white collar round the neck, and a dark gray 
band along the wing coverts. Very young birds are also 
mottled on the mantle. 
Bill of adult coral-red in summer, duller in winter ; young 
birds have a blackish bill ; iris brown ; legs and feet the same 
colour as the bill. 
Length 14; wing 10°5; tail 6°5 ; depth of fork 3-5 ; tarsus 
‘8; bill from gape 2. 
Distribution —An occasional migrant during the north-east 
monsoon to Ceylon and India, most of the birds being im- 
mature. Found throughout the temperate parts of Europe, 
Asia, and North America. 
Habits —Similar to those of the Gull-billed Tern. It is 
only occasionally seen in Ceylon, but in October, 1874, Capt. 
Legge found it plentiful near Trincomalee. 
