DIPTERA OF MINNESOTA. 149 



pears to afford it a safe resting place when not engaged in biting. 

 It is to be noted that when it is resting its wings are pointing back- 

 ward, whereas, while biting, its wings make more of an angle with 

 the body. 



This fly is about half the size of the common house fly, which 

 it very much resembles. Dark colored, particularly black, cattle, 

 suft'er more than light colored animals. Eggs are laid in manure 

 freshly dropped from the animals they attack. Moist weather, by 

 conserving the moisture of the droppings, is conducive to the in- 

 crease of this pest ; hence, a wet and muggy summer will produce 

 more flies than a very dry summer. Some go to the trouble of 

 scattering the droppings in the pasture with a shovel, or by dragging 

 brush across the field, thus insuring the speedy drying of the manure, 

 and the depriving of the larva of its food. Some also place a spade- 

 ful of lime on each dropping — an action which is not always practic- 

 able; furthermore, lime so changes the character of the manure as 

 to make it (the manure) less desirable as a fertilizer. The use of 

 kerosene or kerosene emulsion on cow droppings in the field would 

 be preferable to lime, or (and cheaper) the scattering of the drop- 

 pings, as already suggested. While the use of lime is not desirable, 

 gypsum or land plaster, on the other hand, conserves the qualities 

 of the manure, and may Avell be used on a manure pile in yard or 

 in stable. 



Although this genus and species is troublesome in most of the 

 United States, it is said to cause no trouble in England, where it is 

 also found. The species was introduced into America from Europe 

 probably about 1886, or a little before. Now the horn fly is found 

 in almost every state east of the Rocky Mountains, and in many 

 sections of Canada. I'he irritation and worry caused by their at- 

 tacks result, when the insects are numerous, in loss of flesh, and, 

 in the case of milch cows, a falling off in milk. 



At the Experiment Station a few 3^ears ago we found that a mix- 

 ture of one pound of rancid lard and one-half pint of kerosene, mixed 

 thoroughly until a creamy mass formed, gave excellent results as a 

 preventive, when ru[)bed with a cloth or with the bare hand, not too 

 thickly, over the backs of a few cows, lasting for two or three days, 

 and keeping away all kinds of flies, apparently, which frequent stock 

 here. About three-eighths of a pound was used for each full grown 



