224 SHEEP GAD-PLY. 



be dislodged and removed by a feather dipped in oil of tur- 

 pentine, or a weak solution of carbolic acid, or of creosote. 

 Salt water or diluted carbolic acid solution, injected with a 

 syringe, does good service. Finely powdered lime is also 

 used to cause violent sneezing, thus dislodging the larvae. 

 Some stock breeders smear the noses of their sheep with tar, 

 or force them to do so themselves by attracting the animal 

 to large auger-holes in logs baited with salt, and by coating 

 the rims ' with tar; still others provide in the j^ards dry 

 places covered with deep dust, into which the animals can 

 thrust their noses if pursued by their tormenters. In a few- 



Fig. 182. -Three larvae of sheep gad-flies in frontal sinuses of sheep. Enlarged. Grig. 



cases the writer had an opportunity to use pyrethrum or 

 Persian insect-powder. This material was blown forcibly 

 into the nostrils of the sheep, and dislodged a number of the 

 worms. It can also be used as an extract in alcohol, and 

 will no doubt be very effective, as most dipterous larvae are 

 very sensitive in regard to this substance. 



The illustration (fig. 180) shows the different stages of 

 this insect, and fig. 182 three larvae in the frontal sinuses of 

 a sheep. 



There are a large number of bot-flies which exist in tum- 

 ors they themselves have caused. The genus Ilypoderma 

 especiallj^ contains species that infest domesticated animals, 

 hence these are best known; yet how^ little is really know^n 

 about these parasites is indicated by the fact that until 

 quite recently it was thought that the young larvae forced 



