THE BIRDS OF SOUTH-WEST AND PENINSULAR SIAM- 99 



143. Spilornis cheela bassus (Forst.). 



Falcn hassHS, Foist., Niitui-;j;es(tli. Africiin Vog. 1798, p. 55 (Java). 

 Spilorniit ritUisrfordi, A., p. 14 (partim, Pakc-han ) ; C. ii, p. iSM 



( partim, Tena.s.serim). 

 iSpilornis cheela, D., p. 57 (Patehing and Patani). 

 Spilornis hacha, E., p. 1 1 4 (Patani). 

 S'pilo7'nis pallidus, v., p. 23 (Malay Penin.sula) ; H., pp. 90, 144 



(Bamlon and Koh Samui). 

 "i. Spilornis cJieela rutherfordi, M. 1, p. 28 (Tung Song, Peninsular 



Slum). 



cf. Nanichuk, Pakchan, Peninsular Siam. 25 February, 1919. 

 (No. 4208). 



" Iris chrome ; bill slate ; feet dirty wax-yellow." 



Total length 613; wing 389; tail 275; tarsus 90; bill from 

 gape 44 mm. 



After a careful comparison of large series of these Serpent- 

 Eagles from Siam, Cochin-China, the whole of the Malay Peninsula, 

 Java, Borneo and Sumatra, we are bound to state that we are now 

 unable to recognize with certainty more than two forms, which are 

 only separable on size, viz., a large Indo-Chinese form of which the 

 southern limit Avill be Koh Lak, to which the name 8. c. rutlierfordi 

 has been given, and a smaller Malaysian bird to which, as Richmond 

 shows (Proc. U. S. Nat. Mus., 35, 1909, p. 592, note) the name Falco 

 hassus Forst., applies. In the Malayan area darker coloured as well 

 lighter birds are found, more or le.ss in the same locality, and to the 

 former the name 8. bido Horsf., from Java, applies. Javanese 

 birds, however, can be matched with others from Sumatra and the 

 Malay Peninsula, and Boi-nean birds (*S'. pallidum Walden) with skins 

 from the Malay Peninsula and Sumatra. Spilornis raja -Sharpe, 

 from Borneo, is only the quite immature stage. 



All the Oriental species, with the exception of the Philippine 

 and Celebcsian forms, are certainly subspecies, and the mainland 

 races in physical contact exhibit very obvious gradation. The small 

 Andaman and Nicobar birds are merely depauperated island forms. 



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



56, Xo. '2, 191(5. (first part). 



J. Robinson. Journ. F. M. S. Mus. vii, 1917. Baker, Joum. N. H. Soc. Siam. iii. 1919. 



K. Kloss, n)is, 1918. (second part). 



L. Robinson and Kloss, Joiu-n. X. H. Soc. Siam, M. I. Baker, Journ, X. H. Soc. Siam, iv, )920. 



iii, 1919. Itliird part). 



VOL. V, NO. 2, 1922. 



