CHAP. I. 



WARBLES. 



561 



Sheds out of which diseased animals have been moved should be 

 thoroughly cleansed and disinfected and the litter and manure burned. 

 Where the disorder occurs in the pasture the stock should be removed 

 to a yard thinly littered, in which they should remain for a week or 

 ten days or until fresh cases have ceased to occur, when they may be 

 transferred to a fresh pasture. The field in which the disease arose 

 should not be stocked for at least three months or until the cold 

 season, and then only with horses or sheep or aged beasts. A dose 

 of aperient medicine may be given to the entire herd with advantage, 

 and the further treatment should be relegated to an experienced 

 veterinary surgeon. 



WARBLES. These are small rounded swellings of the skin about the 

 size of a hazel nut. They are found along the backs of cattle in large 

 numbers and have a small opening on the summit. Each swelling 



Fig. 139. 1. Ox Warble Fly, Hypoderma bovis, DeGeer. 1 



3. Chrysalis. 



2. Maggot. 



consists of a grub or larva of the ox warble-fly (fig. 139) buried in the 

 substance of the skin. The egg is deposited on the skin during the 

 months of June, July and August, and the grub (fig. 140) burrows in 

 the hide, remaining there until the following summer when it escapes 

 through the much enlarged orifice (figs. 141 and 142), and falls to the 

 ground, where it remains as a chrysalis, from which the fly eventually 



Fig. 140. Warble 

 Maggots (magnified). 



1. Club-shaped. 



2. Worm-like. 



Fig. 141. Section of 

 Track made by Warble 

 Maggot in Hide (magni- 

 fied) 



Fig. 142. Section of 

 Warble, after Soaking in 



Water. 



emerges. When existing in large numbers warble-maggots induce a 

 good deal of constitutional disturbance and suffering, and prevent 

 cattle from thriving. In some cases they have been known to cause 

 death by " blood poisoning." In all cases they seriously damage the 

 quality of the hide for market purposes (figs. 143 and 144). 



1 Since our last edition appeared it has become known that two varieties of the warble fly 

 are common in the United Kingdom, Hypoderma bovis being most prevalent in Ireland, and 

 H. lineata in England. 



O 



