INSECTS INJURIOUS TO CATTLE 4O3 



grayish white to a dark brownish color. Although they 

 occur on the buffalo of the western plains, it is thought 

 that these animals were not thus affected till after the 

 introduction of cattle. 



The sure indication of the presence of warbles is 

 the small elevations in the skin which may be distinctly 

 traced along the region of the back by moving the 

 fingers flatwise over the same subjected to light pressure. 

 Later, minute openings appear, and these enlarge until 

 the larvae finally escape from them. The infestation is 

 not confined to animals low in flesh, for the eggs are laid 

 at a season of the year when cattle are generally in good 

 condition. 



The injury from warbles, though not very serious 

 in the individual animal, is large in the aggregate. It is 

 felt in the following ways: (i) In the irritation caused 

 by the fly when depositing the eggs; (2) in the weak- 

 ened vitality resulting from the warbles when numer- 

 ously present; (3) in the loss in milk and flesh conse- 

 quent upon these influences, and (4) in the injury done 

 to the hides. The last named is probably the greatest 

 source of loss. It has been estimated that from 33 to 

 jTf per cent of the hides in the upper Mississippi basin 

 are more or less injured by the presence of warbles. 



The remedy should seek to destroy the grubs. This 

 can be done by squeezing them out and destroying them 

 at the proper season. Should the opening be too small 

 to admit of their escape, it may be enlarged by using a 

 sharp knife. Some authorities have also recommended 

 the use of kerosene and mercurial ointment for destroy- 

 ing them. The kerosene may be applied by using a small 

 can of suitable make, but care must be exercised not to 

 use it in excess or it will remove the hair. The ointment 

 is applied by rubbing it over the openings. While the 

 use of the kerosene and the ointment would doubtless kill 

 the grubs, it would seem to be objectionable to have them 

 left in the cells in which they died, and as to the precise 



