BULLETIN 1218, U. S. DEPARTMENT OF AGRICULTURE. 



companies in Nevada, in a communication to Director Doten, stated 

 that the flies were so numerous that they prevented the cattle from 

 putting on flesh as they should, and that at times it seemed as though 

 his company was more engaged in feeding flies than in feeding live- 

 stock. He stated that during the haying season flies swarmed over 

 the horses, causing frequent runaways and serious accidents. Mr. 

 demons believed, too, that the flies were active agents in spreading 



C 



anthrax. 



In 1915 F. C. Bishopp, directing the investigations of insects af- 

 fecting the health of animals, Bureau of Entomology, United States 

 Department of Agriculture, made a preliminary investigation of 

 tabanid conditions in Nevada. In Antelope Valley, on one of the 

 ranches visited, many cattle were dying, presumably from anthrax, 



and there was good evi- 

 dence that blood-sucking 

 flies had much to do with 

 the transmission of the 

 disease. Mr. Bishopp 

 found tabanids to be se- 

 rious pests to livestock at 

 Deeth, Nev.. and at other 

 localities Avliere there is 

 considerable swampy land. 

 In August. 1916, plans 

 were completed with the 

 Nevada Experiment Sta- 

 tion for a cooperative 

 project on an investiga- 

 tion of tabanid conditions. 

 The senior a u t h o r was 

 chosen to conduct the 

 studies in the field. Sev- 

 eral localities were con- 

 sidered for field and labo- 

 ratory studies. None 

 seemed so well adapted as 

 a large ranch occupying 

 practically the entire An- 

 telope Valley, lying partly 

 in California and partly 

 in Nevada, with headquarters at Topaz, Calif. The officials of 

 the company, with major headquarters in Reno, Nev., were very 

 anxious for the investigation. W. W. Cunningham, local manager, 

 offered much in the way of convenience and assistance in the work. 

 Several species of Tabanidae were very abundant in the valley and 

 breeding conditions were apparently ideal. 



The extent of the investigation, limited by lack of funds, is of more 

 than local importance because several of the species studied are of 

 rather wide distribution. It is hoped that the results may be an aid 

 in much needed tabanid studies in other parts of the United States. 



Because of the severe winter climate, the field studies were discon- 

 tinued during the winter months. 



Fig. 1. — Horse-flies feeding upon milk tow, 



