INTERNAL PARASITES 



373 



A hole is made through the sldn by which the grub gets air. These 

 holes are a source of great loss in dressed hides, and the presence of the 

 grub causes irritation and often loss of weight or of milk flow in the 

 infested animal. 



The adult is about the size and shape of a honey-bee, but has only 

 two wings instead of four. The sides of its head and thorax are marked 

 with white, and on the upper surface of the thorax are four shining 

 raised lines. The base of the abdomen is whitish. 



Eggs are laid in early summer attached to hairs near the heels of the 

 animal. The egg opens as the animal licks its heels, and the young 

 grub is carried by the tongue to the 

 mouth. It at once penetrates the 

 walls of the throat and for several 

 months is in the connective tissue 

 along the back of the neck and else- 

 where. Finally it settles under the 

 skin of the back, and makes its breath- 

 ing hole through the hide. When 

 mature, it drops to the ground, where 

 it remains until the next spring. 



The presence of the grub results in damage to the beef, gi\ang it a 

 slimy appearance. In addition the hide is injured. 



Fhes will not lay eggs on animals that are standing in water. In 

 smaU herds strong-smelling oils may be smeared on the lower part 

 of the legs, and will act as deterrents. A mixture sometimes recom- 

 mended consists of sulphur, 4 ounces; spirits of tar, 1 gill; train oil 

 (whale oil), 1 quart. As a rule the adult flies do not enter stables 

 or attack animals under shelter. 



The grubs under the skin are best removed by pressing each side 

 of the hole until the end of the grub protrudes, and drawing it out with 

 tweezers. 



The best time to do this is in February or March. The grubs can 

 be located by passing the hand along the back. If the grubs are thus 

 removed, the flesh beneath wiU heal and the hole will close within a 

 short time. 



Fig 



598. — Larva of the 

 Warble. Original. 



