52 MESSRS ROBINSON AND KLOSS ON 



on botli coasts of Peninsular Siam and breeds there in May and June, 

 lavino- a sino-le eirsf on ledges of bare rock often only three or four 

 feet above high tide. 



There is unfortunately little doubt that S. sumatrana Raffles 

 is founded on a half grown bird of this species, and the name will 

 therefore have to replace the widely known S. melanauchen. 

 Sterna anaetheta anaetheta Scop. 



Sterna anaetheta, Scop., Del. Flor. et. Faun, hisubv. Pt. 2, 1786, 



p. 92 (Pana)') ; A., p. 493 (Mergui) ; Williamson, Journ. Nat. 



Hist. Soc. Siam, ii, 1916, p. 63; id. op. cit. iii, 1918, p. 85 



(Inner Gulf of Siam). 



Probably fairly common, well out to sea, along both coasts of 



Peninsular Siam. It is common in the Straits of Malacca and breeds 



in the Aroa Ids. In the Tioman Archipelago, off the coast of Pahang, 



it is also a breeding bird. 



*Sf^e?'7ia /ui^(7 mosa (Gm.), which differs from the above in its 

 larger size and broader white frontal band and superciliaries, is 

 recorded from Petchaburi by Parrot (Verhandl. Orn. Ges. Bayern, 8, 

 1908, p. 127). It is recorded from Pegu and Tounghoo by Saunders 

 (Cat. Birds Brit. Mus. xxv, 1896, p. 110) and may possibly be found in 

 the Gulf of Siam. We have seen no specimens referable to it 

 from our area. 



55. Sterna sinensis Gm. 

 Sterna sinensis, Gm., Sy.st. Kat. i, 1788, p. 60 (China) ; D., p. 80 

 (Patelung) ; E., p. 119 (Patani) ; Williamson, Journ. Nat. Hist. 

 Soc. Siam, iii, 1918, p. 37 (S. W. Siam). 

 These small terns, except in summer plumage, are extremely 

 difficult to separate, and it is by no means certain that the alleged 

 differences are constant. The present form has the shafts of the 

 outer primaries white, and the size larger, the wing as a rule exceed- 

 incr 180 mm. In the Malay Peninsula it breeds on the sand- 

 banks on the rivers of the east coast for some distance up from their 

 mouths. 



A. Hume & Davison, Stray Feathers, vi, 1878. E. O. Grant, Fasciculi Malnyenses, iii (Birds), 1905. 



B. MuUer, Die Ornis der Insel Salant'a, 1882. F. Rohinson .and Kloss, Hjis, 1910-11. 



C. Oates, Birds Brit. Burinah, Vols, i & ii, 1883. C* Gairdner, Journ. N. H. Soc. Siam, i, 1915. 



D. Bonhote, B. Z. S. 1901, Vol. i. H. Robinson, Journ. F. M. S. Museums, v, 1915. 



JOURN. NAT. HIST. SOC. SIAM. 



