BIRDS FROM SIAM AND THE MALAY PENINSULA 279 



or lack of records from Siam proper may be due to the fact that most 

 of the collecting done there is at a time when the bird is already on its 

 winter range farther south. Diegnan ^^ reports it common in the 

 lowlands of Nan. 



The species can readily be distinguished from the other black 

 drongos of this genus occurring in Siam by its heavier bill and less 

 deeply forked tail. 



DICRURUS MACROCERCUS CATHOECUS Swinhoe 



DicruTus cothoecus Swinhoe, Proc. Zool. Soc. London, 1871, p. 377 (China, Hainan, 

 and Formosa). 



Six males and four females, Bangkok, October 2, 4, 1924, October 

 27 and November 2, 1925, November 30, 1926; one male, Pol, Korat, 

 February 16, 1929. 



This form breeds in Manchuria, northern China, southern China, 

 and the mountains of Szechwan and Yunnan in western China. It 

 is migratory in the northern part of its breeding range but resident 

 in the south. It winters in southern China, Indo-China, Siam, and 

 Burma. 



Gyldenstolpe ^^ says it is common in every part of Siam as far south 

 as Koh Lak; Robinson and Kloss *° record it from Namchuk and 

 Namoh, Peninsular Siam, and Koh Lak, the latter specimen taken 

 April 3. It probably occurs all over Siam in the winter, but it is 

 hard or impossible to tell what records belong to it and what belong 

 to the resident form. 



Five winter males from Bangkok measure: Wing, 140-147 (143.7); 

 tail, 136.5-145 (140); middle tail feathers, 105-111 (107.3); culmen, 

 21.5-22 (21.7) mm. Five males from China: Wing, 138.5-149 

 (143.9); tail, 130-147.5 (135.8); middle tail feathers, 102.5-115 

 (110.3); culmen, 20-22.5 (21.4) mm. 



I much doubt that it breeds in Burma, as recorded by Stuart 

 Baker.*' 



In a rather largo series of this form examined from China, I have 

 never seen in the adult a white rictal spot. 



DICRURUS MACROCERCUS THAI Kloss 



Dicrurus macrocercus thai Kloss, Journ. Federated Malay States Mas., vol. 10, 

 pt. 3, p. 208, 1921 (Koh Lak, southwestern Siam). 



The United States National Museum possesses a pair of this form 

 collected by C. Boden Kloss, the male at Koh Lak and the female at 

 Tachin. 



« Jouru. Siam Soc. Nat. Hist. Suppl.. vol. 10, p. 169, 1936. 



«• Kungl. Svenska Vet.-Akad. Handl., vol. 56, no. 2, p. 20, 1916. 



<« Journ. Nat Tlist. Soc. Siam, vol. 5, p. 341, 1924. 



« The fauna of British India, Birds, ed. 2, vol. 2. p. 358. 1924. 



