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SOME SIAMESE TABANIDAE. 

 By Major E. E. Austen, D.S.O. 



The potentialities of Siam as a field for discovery have hitherto been almost 

 entirely neglected by collectors of Diptera, and in consequence, apart from an 

 occasional description of a new species, little or nothing has been published upon 

 the Siamese representatives of this Order. It follows that the only available method 

 of making determinations of such material is the exceedingly laborious and 

 wearisome one of reading through descriptions of the older authors like Wiedemann 

 and Macquart, which, though based on types collected in other parts of the Oriental 

 Region, may possibly be found to apply to one or other specimen from Siam. 



The following little paper has been prepared in the hope not only of doing something 

 to facilitate the study of Siamese Tabanidae, but also of arousing interest among 

 those who have the opportunity of collecting these insects within the confines of the 

 kingdom of our eastern ally, so that our knowledge may ere long be extended. The 

 fact that the present paper records only a single species in the case of Chrysops, 

 and two species in that of Haematopota, is sufficient indication of its incompleteness ; 

 of the latter genus, at any rate, it is almost certain that many more than two 

 species are to be found in Siam. 



The basis of the paper is a small but interesting collection of Siamese Tabanidae, 

 recently formed and presented to the British Museum (Natural History), by Dr. M. E. 

 Barnes, of the Rockefeller Foundation, New York, and now of Bangkok. In expressing 

 to Dr. Barnes the grateful thanks of the Museum for his kindness, the author desires 

 to draw attention to the interesting field-notes accompanying many of the specimens, 

 which greatly enhance the value of the collection. As a stimulus to others towards 

 further effort in the same direction, it may be pointed out that, of the seven species 

 of Tahanns obtained by Dr. Barnes, no fewer than five appear to be new. 



In order, so far as possible, to extend the scope of the paper, the small amount of 

 Siamese Tabanid material previously in the National Collection has been studied 

 in conjunction with Dr. Barnes's specimens and recorded, or, where necessary, 

 described, in the following pages. Unless otherwise stated, however, every specimen 

 mentioned was collected by Dr. Barnes. 



It is only necessary to add that the types and paratypes of all new species included 

 in the present paper are in the British Museum (Natural History). 



Pangoniinae. 



Genus Chrysops, Mg, 



Chrysops flavocincta, Ric. 



Chrysops flavocinctus, Ricardo, Ann. Mag. Nat. Hist. (7) ix, p. 380 (May 1902). 



Three ?$, Doi Chom Chang, near Chiengmai, 16. iv. 1921. With reference to 

 these specimens. Dr. Barnes writes : " Caught on Doi Chom Chang, while attacking 

 me in a cottage. These flies are very common on the mountain in that region, and 

 are extremely troublesome at a sanatorium situated at an altitude of about 2,500 ft. 

 They were never reported from the top of the mountain (5,500 ft.) until a few cottages 

 were built there, but since that time they are to be found on the peak also. 



