THE BIRDS OF SOUTH-WEST AND PENINSULAR SIAM. 49 



October, which we believe to be this form, but pending the receipt of 

 adult birds in breeding plumage tlie identification is doubtful. Im- 

 mature and winter plumage specimens of H. Jiyhrida appear to have 

 the crown more streaked than in this species. 



48. Hydroprogne caspia (Pall.). 



Sterna casjna, Pall., Nov. Oomm. Petrop. xiv, i, p. 582, tab. xxii, 



fig. 2 (1770). 

 Hijdro'progne caspia, Williamson, Joui-n. Nat. Hist. Soc. Siam, iii, 



1918, p. 37 (Tachin, Inner Gulf of Siam). 



The birds obtained by Williamson at Tachin are the only re- 

 cords for this species from Siam. The bird is the largest of all the 

 terns, with a wing exceeding 400 mm. (16 inches), and with an excep- 

 tionally heavy bill. 



49- Gelochelidon anglica (Mont.). 



Sterna anglica, Mont., Orn. Diet. S'uppl. 1813, fig. (Sussex) ; 



Williamson, Jouvn. Nat. Hist. Soc. Siam, ii, 1916, p. 62 (Innec 



Gulf of Siam). 

 Gelochelidon anglica, A., p. 491 (Mergui) ; H. Saunders, Cat. Birds 



Brit. Mus. XXV, 1896, p, 31., spm. s' (Pakchan). 



Very common in the Straits of Malacca in the winter months : 

 we have not ourselves met with it in Siamese waters. 



50. Seena seena (Sykes). 



Sterna seena, Sykes, P. Z. S. 1832, p. 171 (Deccan) ; I., p. 148 

 (Koh Lak). 



Gyldenstolpe's record of this river tern from Koh Lak is the 



most southerly one. The species is not found in the Straits of 



Malacca, and Kelham's records (Ibis, 1882, p. 201) are referable to 



Sterna media Horsf. We have examined his specimens, which are 



preserved in the Raffles Museum, Singapore. 



51. Sterna bergii pelecanoides (King). 



Sterna cristata, Steph. in ShaAv's Gen. Zool. xiii, Pt. 1, 1825, p. 

 146 (China). 



Sterna pelecanoides, King, Surv. Inter trop. and West Coast Austra- 

 lia, Vol. 2, 1827, p. 422 (Torres Straits). 



Sterna bergii, A., p. 493 (Bokpyin) ; 0. ii, p. 428; E., p. 1 1 

 (Terutau) ; Williamson, Juurn. Nat. Hist. Soc. Siam, iii, 1918, 

 p. 83 (Koh Bin and Koh Chuan, Inner Gulf of Siam). 



!• Gyldenstolpe, Kungl. Sv, Vet. Akad. Handl. M. Baker, Journ. N. H. Soc. Siam, iii, 1919. 



56, No. 2, 1916. (first part). 



J. Eobinson, Journ. F. M. S. Mus. vii, 1917. BakRr, Journ. N.H. Soc. Siam, iii, 1919. 



K. Kloss, Ibis, 1918. (second part). 



L. Kobinson and Kloss, Journ. N. H. Soc. Siara, M.I, Baker, Journ. N. H. Soc. Siam, iv, 19-20. 



iii, 1919. (third part). 



VOL. V, NO. 1, 1921. 



