INJURING CATTLE. 261 



means that one less fly will be present to lay eggs 

 for the coming brood. This should be carefully 

 borne in mind, for from it the conclusion is obvious 

 that if all the maggots present in the backs of cattle 

 of a given neighborhood are killed, the egg-laying 

 brood of flies will be exterminated, and there will be 

 no injury the next season. There is perhaps no 

 other important injurious insect whose numbers can 

 be so readily controlled ; and the experience of Eng- 

 lish farmers shows that by concerted action and con- 

 tinuation of the treatment the amount of warble at- 

 tack may be very rapidly lessened. 



Perhaps the simplest remedy to use during spring 

 and early summer is to squeeze the maggots out of 

 the warbles. When they are nearly full grown this 

 can be done with little trouble ; and when smaller 

 the opening can be enlarged with a pen knife so as 

 to let them out. A pair of medium sized forceps is 

 often helpful in removing them. 



Another simple remedy is to apply to the opening 

 a little oil or grease, which closes the breathing pores 

 of the maggot, thus causing it to die. Kerosene ap- 

 plied to . the warbles either in autumn, winter or 

 spring also destroys them, as does indeed the appli- 

 cation of almost any oily or fatty substance. Train 

 oil or fish oil is especially commended in England. 

 Dr. C. V. Riley says that smearing the animals' 

 backs with this substance " is the simplest and easi- 

 est method of destroying the warbles, which it does 

 by closing the breathing pores on the posterior end 



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