HTDROCHELIDOtf. 307 



Genus HYDRQCHELIDON, Bole, 1822. 



Bill short and slight, moderately compressed ; legs and feet 

 small ; webs between the tor s deeply emarginate, so that the feet 

 appear only half-webbed ; claws long and curved. Wings long, 

 exceeding the tail when closed ; tail short, scarcely forked. All 

 are black or dark grey below in breeding-plumage. 



This genus is widely distributed and comprises four species, of 

 which two are Indian. 



Key to the Species. 



a. Bill from gape about 1 '6 ; only crown and nape 



are black in summer H. hybrida, p. 807. 



b. Bill from pape 1'3 ; head, neck, and lower 



parts black in summer H. leucoptera, p. 308. 



1496. Hydrochelidon hybrida. The Whiskered Tern. 



Sterna hybrida, Pallas, Zoogr. Rosso- Asiat. ii, p. 338 (1811); Hu me 

 S. F. i, p. 281 ; Adam, ibid. p. 403 ; Oates, S. F. iii, p. 348 ; id 

 in Hum's N. $ E. 2nd ed. iii, p. 305. 



Sterna leucopareia, Natt. in Temm. Man. d'Orn. ed. 2 e , ii, p. 746 

 (1820) ; A. Anderson, Ibis, J872, p. 81. 



Viral va indica, Steph. in Shaw's Gen. Zool. xiii, pt. 1, p. 169 (1825). 



Hydrochelidon indica, Blyth, Cat. p. 290 ; Jerdon, B. I. iii, p. 837 ; 

 King, J. A. S. B. xxxvii, pt. 2, p. 218 ; Godw.-Aust. J. A. S. B. 

 xxxix, pt. 2, p. 275 ; Stoliczka, J. A. S. B. xli, pt. 2, p. 256 ; Hume 

 $ Senders. Lah. to Yark. p. 301 ; Hume, N. $ E. p. 648 ; Butler, 

 S. F. iv, p. 32 ; v, p. 235 ; Ball, S. F. vii, p. 233. 



Hydrochelidon hybrida, Hume fy Dav. S. F. vi, p. 491 ; Davids, fy 

 Wend. S. F. vii, p. 93 ; Cripps, ibid. p. 313 ; Hume, Cat. no. 984 ; 

 Lefff/e, Birds Ceyl. p. 996 ; Butler, S. F. ix, p. 440 ; Biddulph, 

 Ibis, 1881, p. 102 ; Scully, ibid. p. 594 ; Reid, S. F. x, p. 86 ; Oates, 

 B. B. ii, p. 419 ; Barnes, Birds Bom. p. 427 ; Hume, S. F. xi, p. 350 ; 

 Sharpe, Yark. Miss., Aves, p. 135 ; Saunders, Cat. B. M. xxv, p. 10. 



Sterna innotata, Beacon, Ibis, 1868, p. 404 ; Hume, S. F. iv, p. 224. 



The Small Marsh-Tern, Jerdon. 



Fig. 70. Head of H. hybrida. 



Coloration in winter. Forehead, sides of head below eyes, sides 

 of neck, and all lower parts including wing-lining white; crown 

 greyish white, with black centres to the feathers, the black increasing 

 on the nape and sometimes almost covering it, and forming a 

 band behind the eye ; a black spot in front of the eye and some 

 black specks on the lores ; behind the nape is more or less of a 

 \vhite collar ; all the upper parts from the neck, including the 



