262 



ORDER DIPTERA 



fully in the Department publications, and from which the 

 statements here made are mostly compiled, have shown 

 that the extent of territory invaded by these insects is much 

 greater than formerly supposed. It may be stated to com- 

 prise, in the worst years, the whole of the Mississippi Valley 

 from the mouth of the Red River, in Louisiana, to St. Louis, 

 Mo. All the adjacent land to the many rivers and that 

 empty from the east and the west into the Mississippi River 



Fig. 207. — Simuliiun pecuarum: larva — enlarged. (From .\nnu: 

 Report of Department of Agrioulture, 1886.) 



is invaded by swarms. They are driven about by the wind 

 and reach points far away from their breeding places. 



The extent of the losses due to this species has already 

 be«n stated, though it is, of course, impossible to separate the 

 losses due to this species from those caused by the turkey 

 gnat. Li a general way the latter may be said to be more 

 destructive to poultry, while the attacks of this species are 

 more particularly directed against the larger domestic 

 animals. 



