SimuliidcB, or Black Flies 107 



materials which will make the densest and most stifling smoke, are 

 often preserved for this use in the spring. Smudges are built in 

 pastures for the protection of stock, and are kept burning before the 

 doors of bams and stables. As the black-flies do not readily enter a 

 dark room, light is excluded from stables as much as possible during 

 the gnat season. If teams must be used in the open field while gnats, 

 are abroad, they may be protected against the attacks of the gnats by 

 applying cotton-seed oil or axle grease to the surface, especially to the 

 less hairy parts of the animals, at least twice a day. A mixture of oil 

 and tar and, indeed, several other preventives, are of practical use in 

 badly infested regions ; but no definite test or exact comparison has 

 been made with any of them in a way to give a record of the precise 

 results." 



"It is easy to drive the flies from houses or tents by burning 

 pyrethrum powder inside; this either kills the flies or stupifies them 

 so that they do not bite for some time thereafter." * * * " Oil of 

 tar is commonly applied to the exposed parts of the body for the pur- 

 pose of repelling the insects, and this preparation is supplied by the 

 Hudson Bay Company to its employees. Minnesota fishermen 

 frequently grease their faces and hands with a mixture of kerosene 

 and mutton tallow for the same purpose." We have found a mixture 

 of equal parts of kerosene and oil of pennyroyal efficient. 



Under most circumstances very little can be done to destroy this 

 insect in its early stage, but occasionally conditions are such that a 

 larvicide can be used effectively. Weed ( 1 904) , and Sanderson ( 1 9 1 o) 

 both report excellent results from the use of phinotas oil, a proprietary 

 compound. The first-mentioned also found that in some places the 

 larvae could be removed by sweeping them loose in masses with stiff 

 stable brooms and then catching them downstream on wire netting 

 stretched in the water. 



Chironomidse or Midges 



The flies of this family, commonly known as midges, resemble 

 mosquitoes in form and size but are usually more delicate, and the 

 wing-veins, though sometimes hairy, are not fringed with scales. 

 The venation is simpler than in the mosquitoes and the veins are 

 usually less distinct. 



These midges, especially in spring or autumn, are often seen in 

 immense swarms arising like smoke over swamps and producing a 

 humming noise which can be heard for a considerable distance. At 



