THE DIPTERA OF MINNESOTA. 



TWO-WINGED FLIES AFFECTING THE FARM, GARDEN, 

 STOCK AND HOUSEHOLD. 



BY F. L. WASHBURN, State Entomologist. 



When one reflects that out of the $795,100,000 which the United 

 States loses annually at the hands, or rather at the mouths, of in- 

 sects, the Hessian Fly alone is responsible for $50,000,000 a year 

 (raised to $100,000,000 in 1900) ; that the loss on hides caused by 

 the work of the Ox \Varble Fly has frequently amounted to $40,000,- 

 000 a year, or higher, in the LInited States; and that our crop of 

 cabbages and cauliflowers is frequently lessened by one-half 

 through the agency of the disgusting Cabbage maggot fly, one can 

 readily see that, in spite of benefits derived from certain members 

 of the order, the members of Diptera, or Two-winged Flies, clearly 

 rank among our serious pests, and are worthy of a special treatise. 



Not only does stock suffer from the Ox Warble, and to a less 

 degree from what we call "horse flies", "deer flies" and "bot flies," 

 but at times and in certain localities it perishes through the attacks 

 of myriads of black flies, the small voracious pest so abundant 

 during summer in northern localities of the United States and 

 Canada as to sometimes cause the death of a man lost in the woods 

 and enfeebled through fatigue and lack of food. Certain domestic 

 animals in South Africa suffer and die through what is called 

 "Nagana" or the "fly disease,"" induced by a germ introduced into 

 the blood by the bite of the notorious Tse-tse Fly. Much more 

 serious than this is the part many two-winged flies play in relation 

 to diseases which cause sufl'ering among hundreds of people, and 

 at times are the active agents in awful epidemics. We refer to the 

 mosquito. Anopheles, whose bite is evidently a necessary means of 

 carrying the malarial germ ; to that other mosquito known as 



