176 THE farmer's veterinarian 



the horse a dose of physic, aloes being best for the 

 purpose. 



GRUB IN THE HEAD.— This condition is the 

 presence of the larva (worm stage) of the sheep bot 

 fly, located in the frontal sinuses (cavities) of the 

 head. The trouble is confined to sheep and occa- 

 sionally goats. The so-called '' grub " of the horse 

 is found in its stomach, while the " grub " of cattle 

 is found along its back just underneath the skin. 

 The adult fly, which lays the living " sheep grub," 

 is of a yellowish-gray color, slightly larger than a 

 house fly. During the warmer part of the summer 

 days the fly goes about depositing its young in the 

 nose of the sheep. The young then work their way 

 upward into cavities of the head between the eyes, 

 but not into the brain cavity. Here they attach 

 themselves to the lining, remaining when un- 

 molested for some ten months, then lose their hold 

 and are sneezed out to the ground. Burrowing 

 into the ground they enter the pupa or dormant 

 stage, when, after a month or six weeks, they 

 emerge as adult flies to replenish their kind. 



When few grubs are in the head little trouble may 

 be observed, but if more numerous may cause free 

 discharge of dirty white or yellowish, thick fluid, loss 

 of appetite, frequent coughing and sneezing, tossing 

 of head and weakened gait, and the animal may be- 

 come too weak to rise, and finally dies. With a special 

 instrument (trephine) bore a hole into the cavity 

 containing grubs and remove them with forceps. 

 When they are present every year the sheep should 

 be protected by keeping the nose smeared with 

 tar during summer months. This can be done by 

 causing sheep to lick salt from holes in a trough 

 after placing tar about the holes. 



