HYDROCHELIDON HYBRIDA. 



(THE BLACK-BELLIED MARSH-TERN.) 



Sterna hybrida, Pall. Zoogr. Eosso-As. ii. p. 338 (1811). 



Sterna leucopareia, Natt. in Temm. Man. d'Orn. p. 746 (1820). 



Sterna javanica, Horsf. Trans. Linn. Soc. xiii. p. 19S (1820). 



Hydrochelidon fluviatilis, Gould, P. Z. S. 1842, p. 140; id. B. of Austr. vii. pi. 31 (1848). 



Viralva indica, Steph. in Shaw's Gen. Zool. xiii. p. 171 (1825). 



Hydrochelidon indica (Steph.), Blyth, Cat. B. Mus. A. S. B. p. 290 (1849); Layard, Ann. & 



Mag. Nat. Hist. 1854, xiv. p. 270; Jerdon, B. of Ind. iii. p. 837 (1864); Legge, 



Ibis, 1874, p. 32 ; Hume*, Nests and Eggs, iii. p. 648 (1875). 

 Hydrochelidon leucopareia (Natt.), Holdsw. P. Z. S. 1872, p. 480 ; Legge, J. A. S. (Ceylon 



Branch), 1874, p. 58. 

 Hydrochelidon hybrida (Pall.), Swinhoe, P. Z. S. 1871, p. 421 ; Von Heuglin, Orn. N.Ost- 



Afr. ii. p. 1449 (1873) ; Salvadori, Uccelli di Born. p. 372 (1874) ; Legge, Ibis, 1875, 



p. 407 ; Saunders, P. Z. S. 1876, p. 640 ; Dresser, B. of Eur. pt. 57 & 58 (1877) ; Hume, 



Str. Feath. 1878, p. 49 (B. of Tenass.), et 1879, p. 115 (List of Ind. B.). 

 The Whiskered Tern, Common Marsh-Tern, Small Marsh-Tern, of authors. Samar Saut, 



Sumatra (Raffles) ; Pater-lahut, Java (Horsfield) ; Kada kuruvi, Ceylonese Tamils. 

 Liniya, Sinhalese ; also Mutheru Kirella, lit. " Sea-Plover," Villagers in the interior. 



Adult male and fundi' (Ceylon). Length 9-3 to 10*8 inches; wing 8-1 to 9-3, reaching when closed to 1-8 beyond 

 tail ; tail 3 - to 3-5 ; tarsus 0-8 to 0*9 ; middle toe 0-8, its claw (straight) 0-42 ; bill to gape 1-5 to 1-8, at front 

 1-05 to 1-1'. 



Breeding-plumage. Iris deep brown ; bill arterial blood-red or dark lake-red, some with the culmen dusky ; inside of 

 mouth and gape bright red ; legs and feet arterial blood-red, claws black. These are the normal tints of the soft 

 parts in the breeding-plumage; but the tone of the colour of the bill and feet vary. 



Fl male (Ceylon, April). Forehead, head, and nape black, passing from the bill to the lower anterior edge of the eye, 

 and from the same position behind the eye to the nape ; lower portion of lores, face, and ear-coverts white ; the 

 lower eyelid black : hind neck, back, scapulars, wing-coverts, upper tail-coverts, and tail dark blue-grey, the wing- 

 coverts and tail slightly paler than the back ; outer web of lateral tail-feathers white ; inner webs of the prima- 

 ries brownish grey, the basal portion white, running out in a point into the brownish, the outer webs and tips 

 " frosted " t white when the feather is new ; primary-shafts white ; secondaries and tertials delicate grey, the 

 former tipped with white ; chin white, passing into faint grey on the throat, and gradually darkening on the 

 fore neck and chest into the pure grey-black of the lower breast, abdomen, and flanks ; rump and under tail- 

 coverts white ; axillaries and under wing white. 



Male (Southern Europe). Darker on the back, and the black of the lower parts deeper than in several female examples 

 from Ceylon. In my own collection there are no male specimens in perfect summer plumage. 



Winter plumage (Ceylon). Bill (variable) blackish red, dull red, almost black in some ; legs and feet likewise varying 

 from dark reddish to dull lake. 



* I cannot, for want of space, continue to give more than the leading Indian references. 



t The delicate " frosting " or " silvering " of the outer primary-webs in this family of birds speedily wears off, and 

 exposes the dark grey ground-colour of the feather. 



