THE TiPULffi. 523 



Of the sheep gad fly. 



selves, and the larvse crawi about till they die; 

 others are washed off by the water, &c. 



The perfect fly is very tender, and but ill sus- 

 tains the change of weather, and cold and mois- 

 ture in any considerable degree are probably 

 often fatal to it. 



The manner in which the female sheep gad-fly 

 deposits her egg has been seldom noticed ; nor 

 is it easy, from the obscure and rapid motion of 

 the insect, tb discern the exact manner in which 

 this is accomplished. The moment the flie stouch 

 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 

 also smell the grass as they go, lest one should 

 be lying in wait for them. If they observe one, 

 the} r 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 conse- 

 quent rubbing against the ground, that the nos- 

 tril becomes highly inflamed and sore, and occa 

 sions their touch to be so much dreaded by the 

 sheep. 



The tipulse, or crane-flies, have, in their gene- 

 n.in ; <-u/; 3 3 



