[19] Report of the State Entomologist, 115 



has been made, and the larvse within the warbles killed, there was 

 nearly an entire exemption from attack the following years. 



The warbles are easily to be found during the months of March 

 and April, by passing the hand over the back of the animal on each 

 side of its spine, when, if any are present, they will at once be detected. 

 On examination, an opening will be seen leading into the warble, and 

 closely applied to it, the black-tipped tail of the larva within may be 

 discovered, drawing in the air needed for its sustenance. 



The old method has been to postpoae all attention to the warbles 

 until the month of May, when their contents can easily be forced out 

 by a gentle pressure with the fingers. But this delay, from the 

 greater irritation produced by the rapid increase in the larval growth, 

 entails much increased siijffering upon the infested anitnal, and 

 consequent detriment to its health and condition. 



Careful examination of the stock should be made as early as in 

 February, when opened warbles may often be discovered. As soon 

 as they are found in this stage of advancement, a small quantity of 

 mercurial ointment should be applied to the opening, with such 

 pressure as shall cause it to reach the end of the larva lying against 

 the hole. The larva will be killed by the ointment, and its decom- 

 posed material discharged in two or three days thereafter, and the 

 healing of the warble will immediately follow. 



It has been stated that if, whenever the presence of warbles can be 

 detected, whether in the autumn or during the winter, mercurial 

 ointment be rubbed upon them, it will be absorbed thi'ough the skin, 

 and cause the death of the larva within. Kerosene is said to have the 

 same effect; but we can not vouch for the ef&cacy of these methods 

 of treatment. 



Instead of the above ointment, almost any thick, sticky, greasy 

 matter, such as rancid butter, lar^^ or cart grease^ applied to the 

 warble in such a manner as completely to close the opening, will kill 

 the grub, as its life can only be sustained by the air which it draws 

 through the hole into the breathing pores at the tip of its abdomen. 

 A bit of tar has been successfully used for the purpose. 



The Ox Gad-Fly. 

 Another species of fly infesting the ox, which in the minds of many 

 persons is confounded with the warble-fly, although of very different 

 habits, is the ox gad-fly, Tahanus hovinua Linn., represented, after 

 Ormerod, in Figures 7 and 8. This species is mentally associated 

 with a galloping herd of cattle with their tails in mid-air and 

 mouths wide-sj^read in bellowing, rushing madly over their pas- 

 tures to find relief in a plunge in water, as has been so often 



