DISEASES OF FARM ANIMALS 125 



partially developed in the digestive tract. It then 

 burrows through the tissue until it reaches the 

 region of the back. The only treatment that will 

 amount to much is to destroy the grub as it is 

 developing under the skin. If farmers and stock- 

 men will systematically do this they can soon les- 

 sen the damage done. The heel fly annoys cattle, 

 and the grub, when it escapes from the back, 

 leaves a hole in the best part of the hide, causing 

 loss in this way. After the grubs are in the back 

 no treatment helps the animal very much ; but the 

 grub can be killed, thus preventing their develop- 

 ing into flies that would annoy other cattle. The 

 grubs may be squeezed out and destroyed. Mer- 

 curial ointment may be rubbed through the hole 

 and kill the grub, or chloroform, or creoline, may 

 be injected into the grub with a hypodermic 

 syringe. It does not require very much time to 

 look after the number of cattle usually found on 

 a farm. 



The Bot-Fly of Sheep is a very troublesome pest 

 at times, and always causes trouble and annoyance 

 to the flock when present, and occasionally causes 

 considerable financial loss. The fly attacks sheep 

 during the warm months, July and August gen- 

 erally being the worst. The presence of fly in the 

 flock is easily told by the behavior of the sheep. 

 The fly looks much like a house fly, only it is longer 

 and it always attempts to lay its eggs just inside of 

 the opening of the nose. As soon as the fly begins 

 to get near the nostril the sheep will begin to run, 

 will hold their noses close to the ground, and fre- 

 quently huddle together as closely as possible for 

 protection. When the fly does succeed in deposit- 

 ing the larvae it begins immediately to work its 

 way up the cavity of the nose and finally gets 



