1507. Sterna longipennis.
Sterna longipennis, Nardmann in Erman's Reise, p. 17 (1835) ; Hume, Cat. no. 986 bis; Saunders, Cat. B. M. xxv, p. 67. Sterna tibetana, apud Hume, S. F. viii, p. 158, nec Saunders.
Coloration. Similar to that of S. fluviatilis, except that the bill is always black and the feet are blackish. Adults are darker in colour, both above and below, but the difference is not great. All the measurements appear identical, or nearly so, except those of the bill, which is altogether smaller, and measures about 1.75 from the gape.
Distribution. The Eastern coasts of Asia and the neighbouring islands from Kamtchatka to New Guinea. Immature specimens identified by H. Saunders have been obtained in the Malay Peninsula by Davidson and others ; and one example, now in the British Museum, was collected by Legge in Ceylon, in June.