Gammon Parasites 



31 



short and broad. The ticks 

 have three pairs of legs. 

 Body and legs are covered 

 with fine short hair. The 

 eggs produced by the fe- 

 male are flat, oval and of 

 brownish color and are 

 fastened to the wool fibres 

 with a sticky substance. 

 The young emerge from 

 the shell in the nymphal 

 stage of development and 

 in form are identical with 

 the adults. The entire life 



_, ,** cycle is passed on sheen. 

 FIG. 2tt Adult sheep tick (a) and pupanum (6) 



(Melopluigus ovinus). Enlarged. (After Osborn, Symptoms. Long wool- 

 1896; Bui. No. 5, Div. Entomology, Dept.Agr.) ed sheep are more subject 

 to tick infestation than short wooled. Infested sheep show evidences 

 of restlessness and irritation of the skin. Unthriftiness and loss of 

 vitality are caused by the parasites sucking blood, eating flesh and 

 destroying the wool fibres. 



Treatment. Carefully examine all new sheep before placing them 

 with the flock. Dip infested sheep in kerosene emulsion or in cresol 

 solution as recommended for lousiness. 



Bot Fly of Sheep (Oestrus ovis), (Sheep gad fly). 

 This is a small greyish yellow fly. The body is covered with fine 

 hair and the abdomen marked with five rings. 



Life History. The flies are present during the hot months during 

 the heat of the day. This fly does not produce eggs but deposits 



living larvae in the region of the nos- 

 trils. The larvae pass up into the 

 nasal chambers and cavities of the 

 head where they fasten themselves to 

 the membranes by means of hooks 

 with which their heads are armed. 

 The period of larval development is 

 ten months. During this time the lar- 

 vae grow to a length of % inch and 

 diameter of % inch. When full de- 

 velopment is attained they release 

 their hold and are sneezed out and 

 drop to the ground. They then bur- 

 i row into the ground and lie dormant 

 during four to six weeks. From this 



Brauer.) b, Larva or grub from fully developed adult flies, 

 nos? of sheep. Enlarged. (After Symptoms. When sheep are pur- 

 Curtice.) sued by the flies they run among 



