42 NOVITATIIS ZOOI/OOICAE XXVI. 1919. 



HMtat. The Sub-Himalayas and adjoining country of Northern India 

 from Nepal to extreme east and south of Assam, the whole of the tracts of lower 

 hills in Burma, Malay Peninsula, and Northern Siam. 



(2) Dicrunis annectens siamensis. 



Dicrurus annectens siamensis Kloss, Ibis, 1918. p. 226. 



Type in Museum Fed. Malay States. 



Type Locality. Koh Lak, S.W. Siam. 



Size a trifle larger, wing averaging 144- 5 mm. ; biU decidedly less broad, 

 measuring only about 8' 5 mm. at the nostrils, also generally less deep and a little 

 shorter, but by no means constant in the two last respects. 



Habitat. Central, South, and Peninsular Siam. The boundaries of this form 

 cannot be given at present with any degree of certainty, Gyldenstolpe did not 

 meet with it in North and North Central Siam. 



It must be remembered that Malayan birds generally, including those from 

 Peninsular Burma, have bills of 11 mm. in breadth, larger than anywhere else, 

 although in geographical position they are nearest to Kloss's siamensis. This 

 is a fact that makes one doubt if, eventually, this sub-species wiU not have to be 

 suppressed. 



Bhringa remifer. 



This Drongo follows the universal, or almost universal, rule in Indian and 

 Burmese birds and becomes somewhat smaller and smaller as one follows it 

 through from north to south. The diminution in size is not, however, quite so 

 marked as it is in many other instances, whilst, on the other hand, the extent 

 of over-lapping is even greater. This is shown in the following table : 



Area. Wing, e^remes. Average. ""vl'^S^ 



(1) Nepal to Sikkim . . . 132'0 to 146'0 mm. 



(2) Assam to Manipur . . . ISl'O to 143'0 mm. 



(3) Upper Chin and Shan Hills . . 133'0 to U2-0 mm. 



(4) Central and South Burma . 129'0 to 137*0 mm. 



(5) Java 1300 to 1370 ram. 



(6) Sumatra 1280 to 132-0 mm. 



(7) Mt. of Perak and Pahang . . 127'0 to 134-0 mm. 



As regards division by size it is only the first four of these areas which need 

 consideration, as birds from ( 5) and ( 6) are easily separable on account of their 

 very small outer tail feathers, the racquets of which are smaller — both shorter 

 and narrower — than in birds from other parts ; whilst No. 7 is differentiated at 

 once from all other geographical races by the quite different formation of the tail. 



After some consideration it seems advisable to retain all those birds found 

 in the four areas first enumerated under one and the same name. Principally 

 I come to this conclusion because nowhere can a line be drawn where it can be 

 said that the majority of birds on either side of it are larger or smaller, and no 

 definite area exists in which the size is in any way constant. Again, there are 

 no colour or structural differences which help to support the differences in average 

 measurements. 



I therefore recognize the following three races only : 



