THE BIOLOGY OF TABANUS STRIATUS FABRICUS, THE 

 HORSEFLY OF THE PHILIPPINES 



By M. Bruin Mitzmain 



(From the Veterinary Division,'^ Bureau of Agriculture, Manila, P. I.) 



Seven plates 



The importance of investigating the bionomics of insects ca- 

 pable of transmitting disease need not be emphasized. However, 

 the paucity of literature on this subject leads one to suspect 

 that insects as pathogenetic factors are not sufficiently appre- 

 ciated by the entomologist. Too often this negligence of the 

 entomologist has to be corrected by the overburdened research 

 v^^orker in medicine, in order to supply important links in the 

 etiology and transmission of infectious diseases. 



Tabanus striatus Fabricus ^ is the most prevalent horsefly of 

 the Philippines. It has a possible economic bearing relative to 

 trypanosomiasis, in as much as it is found wherever surra is 

 abundant, and the seasonal distribution of the fly and the disease 

 are in a measure coincident throughout the principal regions of 

 the Archipelago. In Manila and within a radius of 50 kilo- 

 meters this Tabanus is found rather continuously from October 

 to March. It is during this period that surra outbreaks in 

 this region are the most prevalent. It is during this period 

 also that other species of bloodsucking flies have their seasonal 

 preponderance. Species of Tabanus have been experimentally 

 incriminated in the transmission of surra in India, in North 

 Africa, and elsewhere. In the Philippines Tabanus has never 

 been proved to be a carrier of trypanosomiasis. At the present 

 time this fly is the subject of an experimental investigation to 

 determine its relation to the spread of surra. With this purpose 

 in view, it was found essential flrst to breed the fly preparatory 

 to use in transmission experiments, and the data collected and 

 presented here are the results of the rearing of thousands of 



* Archibald R. Ward, chief. 



' I am indebted to Professor James S. Hine of Ohio State University 

 and to Mr. Austin of the British Museum for this identification. 



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