88 MA.NTAL OF PHILIPPINE BIRDS. 



upper and greater part of the inner webs; upper tail-coverts gray; tail- 

 feathers gray, with white outer webs to the outside pair; chin white or 

 very pale gray; throat gray, darkening on the lower part; breast dark 

 slate-gray, which deepens into black on abdomen and flanks; vent and 

 under tail-coverts white ; under wing-coverts white ; axillars white with a 

 faint tinge of gray. Bill blood-red; feet vermilion, drying to orange- 

 color; webs deeply indented, but less so than in H. leucoptera. Length, 

 280; culmen, 35; wing, 235 to 241; tail, 96; tarsus, 23; middle toe with 

 claw, 29. 



"Indian birds, which are probably almost sedentary, are slightly smaller 

 in size. Some of the birds resident in South Africa are of a distinctly 

 darker hue both above and below than northern examples; Australian 

 specimens, on the other hand, are inclined to be paler. 



"Adult female. Similar to the male, or a trifle paler in general tint. 



"Adult in winter plumage. Upper parts of a paler gray than in the 

 breeding season; forehead white; crown and nape streaked and mottled 

 with black; under parts entirely white; bill and feet reddish brown. 



"Young in first plumage. Crown and nape blackish brown, mantle 

 mottled with brown and with warm cinnamon-brown edges to inner 

 secondaries; tail slightly mottled and edged with ash-brown; the rest like 

 the adult in winter. By December the brown markings are considerably 

 diminished. 



"Nestling. Down at .the base of bill black, forehead ruddy fawn-color ; 

 upper parts paler fawn, mottled and streaked with black; under parts 

 white, except the throat, which is sooty black for a few days." 

 (Saunders.) 



"Common about the Pasig River and Laguna de Bay. Several flocks 

 were observed in Mindanao feeding over the paddy-fields." (Bourns and 

 Worcester MS.) 



Genus STERNA Linnaeus, 1758. 



Bill much as in Hydrochelidon but somewhat longer; toes completely 

 webbed ; tail always distinctly forked ; outer rectrices usually much longer 



than the others. 



Species. 

 a 1 . Crown black. 



ft 1 . Larger; wing, 240 mm. or more. 

 c 1 . Forehead black to base of culmen. 



d 1 . Larger; tarsus yellow or red; bill red in summer hirundo (p. 89) 



eP. Smaller; tarsus blackish, bill black at all seasons.... longipennis (p. 89) 

 c 8 . Forehead white. 



d 1 . Lores white boreotis (p. 90) 



d 3 . Lores black. 



e 1 . Wing, 265 mm.; mantle umber-brown anaestheta (p. 91) 



e-. Wing, 300 mm.; mantle deep black fuscata (p. 92) 



ft 2 . Smaller; wing less than 200 mm sinensis (p. 92) 



a a . Crown white melanauchen (p. 93) 



