REPORT OF THE ENTOMOLOGIST AND BOTANIST. 187 



over the Kerosene, and further trials soon showed that animals after four or five 

 days from time of spraying with Fish-oil emulsion were free from attack of flies, 

 while those upon which Kerosene emulsion had been used weie more or less 

 annoyed." (^Louisiana Exp. Station Bull., 2nd series, No. 22.) Fish-oil emulsion 

 differs from Kerosene emulsion only in the substitution of fish-oil for coal oil 

 or kerosene. 



A good way to fight this pest will doubtless be to prevent it from breeding and 

 increasing. As stated above, the maggots can live only in the moist droppings of 

 cattle. Any means, therefore, which will insure the drying up of these before the 

 maggots uje full grown, will destroy them. This can be done most easily by spreading 

 the dung out in the pastures regularly and at short intervals. Twice a week would be 

 sufficient, and it would be equally effective in wet weather when the substance would 

 be washed away, as in hot weather when it would be dried up. 



Where the flies gather in large numbers, on the ceilings and walls of stables in 

 cool weather, or when driven from the cattle by applications, they can be destroyed 

 by spraying them with either Kerosene emulsion or a strong decoction of Pyrethrum 

 Insect Powder. Dusting them with dry Pyrethrum powder by means of an " insect 

 gun " would also be effective. 



In studying the history of this insect since it first appeared in North America 

 in 1887, 1 have noticed that at the places where some years ago its attacks were very 

 severe, it is now much less troublesome. I was, therefore, led to hope that after a 

 time, the considerable loss which Canadians are now suffering from the Horn-fly, 

 would be much less. Correspondence with entomologists confirmed this view. In 

 reply to letters, onthis point and with regard to any new remedies which might 

 have been discovered, addressed to the United States Entomologist, and other specia- 

 lists who have studied this pest, I have received the following : — 



" Yours of 25th has l^een received during Prof. Eiley's absence. We have found 

 nothing better than Kerosene emulsion for the protection of cattle from the Horn- 

 fly. In answer to your second question, I may say that it has been almost the 

 invariable rule that the second year the flies are worst, and after this bad second 

 year the numbers are fewer. We have explained this on the ground that native 

 parasites preying ordinarily on native dipterous larvae in cow-dung acquire a taste for 

 the Horn-fly larvae after a short time." — L. 0. Howard, Acting Entomologist, 

 Washington, D.C. 



"Concerning the Horn-fly, I have nothing new in the way of remedies. As I 

 have stated on several occasions, the insect is not now troublesome in our State, and 

 there is no necessity for applications of any kind to cattle. Our farmers found 

 fish-oil with a little carbolic acid to be much the most satisfactory material that 

 could be used, and I never could induce any to try the Kerosene emulsion, A 

 propos of this, at the Madison meeting of the Association of Economic Entomolo- 

 gists, in the course of a discussion, almost all those who had been advocating the 

 use of Kerosene emulsion on live stock, stated that they did not further recommend 

 it, because of the difficulty of getting farmers to make it properly, and of the danger 

 where it is not properly made." — Prof. John B. Smith, New Jersey Agric. Coll. 

 Exp. Station. 



Prof. W. B. Alwood, of West Virginia, has found that the stock emulsion 

 diluted ten times and mixed with one part of water extract of tobacco waste (made 

 by steeping 1 pound of tobacco stems in 1 gallon of hot water for an hour or more), 

 gave almost perfect immunity for a period of three days, and that two treatments 

 per week almost entirely relieved his cattle from annoyance. He makes the appli- 

 cation with a knapsack pump fitted with a cyclone nozzle, and the work is done 

 just after milking time. His method is as follows: — The animals are driven into an 

 inclosure through a gate which will only admit one at a time. A man with a knap- 

 sack pump on his back stands at the gate and sprays one side of each animal as it 

 passes ; they are then driven out again, and the other side is treated in the same 

 manner. The quantity of liquid thus applied is very small, but has been found 

 sufficient. 



Prof. Alwood writes recently : — " Concerning treatment of Horn-fly I am pro- 

 ceeding still just as given in my note at Washington meeting. (^See above). Of 



