INTRODUCTION. 



Among the many injurious insects with which the farmers 

 and planters of Louisiana have to contend, few are of more 

 importance than the insects known as horseflies, deerflies and 

 earflies. All of these flies, belonging to the group of insects 

 known to entomologists as the Tabanidae, at times reach enor- 

 mous numbers in parts of Louisiana. In fact, it is doubtful if 

 any of the scientists who have touched, in their publications, 

 upon the importance of these insects, or upon their role in the 

 tlissemination of disease, have had even a remote conception of 

 the enormous numbers of these flies which at times infest cer- 

 tain of the coast and alluvial sections of Louisiana. 



Aside from their direct damage in reducing the flesh of the 

 animals attacked and in preventing the growth of young stock, 

 these flies are instrumental in the dissemination of anthrax, or 

 -eharbon, a disease which has from time to time during the past 

 one hundred years or more, ravaged the herds of Louisiana and 

 stood as an almost insurmountable barrier to the successful and 

 profitable production of beef and dairy cattle, which thb climate 

 and abundant forage of the State would otherwise make possible. 



While charbon outbreaks usually originate by an animal ob- 

 taining, while grazing on infected pastures or headlands, the 

 spores of the disease, its further dissemination to plantation 

 feed lots and stables is almost entirely through the agency of 

 these flies, w r hich, after feeding upon either the diseased live 

 animal or upon the cadaver, fly to animals throughout the en- 

 tire neighborhood, carrying with them the anthrax spores mid 

 bacilli. 



Could the horseflies be exterminated in any given locality, 

 'or even considerably reduced in numbers, the control of this 

 disease and its ultimate eradication would be rendered much 

 easier than at present. 



The first step looking to the successful control or eradica- 

 tion of any insect must be the acquisition of a thorough knowl- 

 edge regarding its life history and development. The develop- 



