13 
tion,* but the results were most unsatisfactory, the great majority 
of the flies abandoning the cattle at the moment of entrance, so that 
only about 5 per cent of the flies were captured. 
Destruction of larve and pupe—The destruction of larve and 
pup in the dung by direct measures and consequent reduction in 
the numbers of the adult insects is a possible means of control, not, 
however, always practicable, and having little utility in the case of 
range animals. ‘Two methods of locally destroying the flies in the 
dung have been shown to be fairly effective. A spadeful of lime 
thrown on cow dung will destroy the larve living in it, and in small 
pastures such treatment of dung, especially at points where the cattle 
are more apt to congregate, may be feasible. This treatment is espe- 
cially useful if carried out during May and June, as every larva killed 
of the early broods means a very large reduction in the number of 
flies for midsummer and later in the season. 
Prof. J. B. Smith suggests another means of control, namely, the 
spreading out of the fresh dung with a shovel, which causes the rapid 
drying of the dung and the destruction of the Dipterous larve con- 
tained in it. This method also is feasible only in the case of small 
pastures and in dry weather. An inexpensive method, suggested 
by Mr. D. L. Van Dine, of scattering the dung in yards and pens and 
causing it to dry quickly is to allow a number of pigs to run with the 
cattle.. In their efforts to obtain undigested particles of food the 
pigs will effectually destroy the dung as breeding places for the fly, 
at least during dry periods. 
A dairyman in Texas, as reported by Mr. Hunter, has followed an 
analogous method of control which has given him very considerable 
protection from the horn fly. He makes it a practice to collect 
daily the dung in and near the dairy barns, and every few days this 
collected material is taken out and distributed with a spreading 
machine on the pasture, so that it promptly dries up and the breeding 
of larve in it is prevented. Wherever this practice-is feasible it is 
to be strongly recommended, and has the important additional argu- 
ment in its favor of conserving the valuable manurial material which 
might otherwise go to waste. 
In the same way, as observed by Mr. Mitchell, during the dry 
period of July and August in western Texas the foes fly is very much 
reduced in numbers by the rapid desiccation of the cow droppings. 
Approved: 
JAMES WILSON, 
Secretary of Agriculture. 
Wasuineton, D. C., November 17, 1909. 
a Kansas State Agr. Coll. Exp. Sta., Press Bul. No. 49, November 7, 1899. 
[Cir. 115] 
O 
