The Plague of Flies. 21 



and lessened vitality, then the bill for this creature alone 

 in 1900 was $109,756,000. Buffalo gnats were reported 

 to have caused a loss of $500,000 to horses and mules in 

 a single county of Tennessee in 1874. The worst of it 

 is that these Mies attack draught animals at the time 

 uhen they are most needed to prepare the ground 

 for crops, when every day is 

 valuable. 



There is something particu- *""*' ^ 



larly fiendish, it seems to me, in 

 the way these flies devil the lives 

 out of horses and cattle. The 

 poor animals nearly go out of 

 their minds frum the tormenting 



i , A ,i i . i- Fig. 2. H\poderma bovis, 



bites. A cow that ought to live ox . bot fly orwarblefly . 

 in peace and quiet, devoting all 



her energies to putting on flesh or getting milk ready 

 for the city market, is made to gallop all around till 

 she is as thin as a rail and as tough as rubber, while 

 all her milk is scared back into her blood. It isn't 

 the mere pain of the bite that drives them frantic 

 with terror, for the flies that scare them worst the 

 warble and the heel-fly do not bite. They lay their 

 eggs on the hairs just above the hoof, where the cow 

 will lick them off. The egg hatches in the mouth 

 and the larva has barbs on it, so as to work its 

 wav into the walls of the throat. Once there, it molts 



* 



and becomes smooth, so that it can slide about for 

 months through the tissues between the hide and the 

 flesh. It finally reaches the skin along the back, molts 

 again and takes, on spines, with which it bores a hole out 

 to the air. It creates an open sore, in which it fattens. 

 \\ hen it is about to mature it comes out, drops to the 

 ground, contracts and hardens, and in from three to six 



