86 “MANUAL OF PHILIPPINE BIRDS. 
Family LARIDZA. 
Characters same as those ivel foe the Order. 
Subfamilies. 
a’, Tail more or less forked (except in Anous); bill slender; terminal portion 
of culmen straight or but slightly curved; angle of lower mandible not 
PTOMINENt  ......-------n---eeececeeeeeeee ces eee eeeeeneeeneenanensntenesaeceneenecenenenes Sternine (p. 86) 
a. Tail even; bill stouter; terminal portion of culmen decidedly curved; angle 
Gl WOWwer Waudi ble aUSbin Cbs ce ores cece sean eee eer cenee Larine (p. 95) 
Subfamily STERNIN 4. 
The members of this subfamily afford no very tangible chafacters to 
distinguish them from the gulls other than those already mentioned. 
However, the terns are, as a rule, of more slender form and more airy 
and graceful flight. The wings, bill, and tail are proportionately longer 
and the body smaller than these parts in the gulls. 
Genera. 
a’, Tail more or less forked. 
bt. Tail but little more than one-third of wing, its outer feathers broad and 
rounded):\ 2.408 eed ee Lee EE ree ee ee Hydrochelidon (p. 86) 
b?. Tail much more than one-third of wing, its outer feathers narrow and pointed. 
Sterna (p. 88) 
a. Tail graduated ;) plumage sooty bYrOwml-2-2..2-5..-f:-qseccere ee eecerceerntoees Anous (p. 94) 
Genus HYDROCHELIDON Boie, 1822. 
Bill short and slender; legs and feet small; webs between the toes 
deeply emarginate; wings long, when closed, exceeding the tail; tail 
short, nearly square. 
Species. 
a*. Black or dark gray below (adults in summer). 
b'. Upper tail-coverts and tail white; under wing-coverts black. 
leucoptera (p. 86) 
b*. Upper tail-coverts and tail gray; under wing-coverts white.. hybrida (p. 87) 
a?, White below (adults in winter and young). 
(Thies) BWR 5 9 SAO ae ae = A EAA GMMR et 084 He leucoptera (p. 86) 
6%. Tail gray. 
sor! ARES 0 Sa edd] 1) eae cw ne a pL HE ROM PAE ote hybrida (p, 87) 
7. Rumpawhite:' (voting i024. oe Ee ee ato Seated leucoptera (p. 86) 
76. HYDROCHELIDON LEUCOPTERA (Meisner and Schinz. ) 
WHITE-WINGED BLACK TERN, 
Sterna leucoptera MEISNER and ScHINZ, Vog. Schweiz (1815), 264. 
Hydrochelidon leucoptera SAUNDERS, Cat Birds Brit. Mus. (1896), 25, 6; 
SHARPE, Hand-List (1899), 1, 133; Oarres, Cat. Birds’ Eggs (1901), 
1, 174; McGrecor and WorcrEstTER, Hand-List (1906), 20. 
Mindanao (Steere Bap., Bourns & Worcester). Central and southern Europe 
to central Asia and China; Australia, New Zealand, Africa in winter. 
