THE BIRDS OF SOUTH-WEST AND PENINSULAR SIAM. 99 



143. Spilornis cheela bassus (Forst.). 



Falco hassus, Forst., Naturgesch. African Vog. 1798, p. 55 (Java). 



^Sjnlornis rutherfordi, A., -p. 14 (|x«-«m, Pakchan ) ; 0. ii, p. 194 

 (23<''i'}'ti'>n, Tenasserim). 



Spilornis cheela-, D., p. 57 (Patelung and Patani). 



Spilornis bacha, E., p. 114 (Patani). 



Spilornis 2}allidus,F., p. 23 (Malay Peninsula); H., pp. 90, 144 

 (Bandon and Koh Samui). 



? S2nlornis cheela rutherfordi, M. 1, p. 28 (Tung Song, Peninsular 

 Siam). 



S. Namchuk, 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 will be Koh Lak, to which the name 8. c. rutherfordi 

 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 

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

 lighter birds are found, more or less in the same locality, and to the 

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

 birds, however, can be matched w^ith others from Sumatra and the 

 Malay Peninsula, and Bornean birds (S. ijallidus 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 Celebesian 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. 



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



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



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



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



L. Robinson and Kloss, Journ. N. H. Soc. Siam, M. I. Baker, Journ, N. H. Soc. Siam, iv, 1920. 



iii, 1919. (tlurd part). 



VOL. V, NO. 2, 1922, 



