[ 4H 3 



THE SHEEP GAD-FLY*. 



The manner in which the Gad-fly of the Sheep 

 deposits its egg has been seldom noticed ; nor is it 

 easy, from the obscure and rapid motion of the in- 

 sect, to discern the exact manner in which this i$ 

 accomplished. The moment the flies touch the 

 noses of the sheep, they shake their heads, and 

 strike the ground violently with their fore feet : at 

 the same time, holding their noses to the earth, they 

 run away, looking about them on every side to see 

 if the flies pursue. They also smell the grass as 

 they go, lest one should be lying in wait for them. 

 If they observe one, they gallop back, or take some 

 other direction. As they cannot, like the horses, 

 take refuge in the water, they have recourse to a 

 rut, or dry dusty road, where they crowd together 

 during the heat of the day, with their noses held 

 close to the ground. This renders it difficult for 

 the fly conveniently to get at the nostril. It is most 

 probably from repeated attacks, and the consequent 

 rubbing against the ground, that the nostril becomes 

 highly inflamed and sore, and occasions their touch 

 to be so much dreaded by the sheep t« 



* Oestrus Ovis. Linn* f Linn. Tran. iii. 313. tab. 33, 



