THE SHEEP EOT FLY. 213 



rid of. Spirits of tar may be used freely with the same good 

 effect. Fluid mixtures compounded for the purpose may 

 also be purchased of any druggist in a sheep-farming district. 

 The colouring matter which is applied to rams or show sheep 

 is often ostensibly applied as "fly powder." The object, no 

 doubt, is twofold, as the powder is coloured according to taste, 

 and is employed as a means of decorating an animal intended 

 to appear before the public. It, however, possesses an actual 

 use, as it keeps away the flies from animals which it is par- 

 ticularly desirable should not be disfigured in any way. 



When maggots are neglected the sheep pulls out his wool 

 with his teeth, and, later, the skin becomes hard and dry, and 

 the wool comes off very much in the same manner as if the 

 skin had been scalded or burnt. The use of fly powder is 

 relied upon to prevent these injurious effects, which would 

 ruin any sheep intended for exhibition, or for appearing in a 

 sale ring as a ram. 



THE SHEEP BOT FLY (CEsxRus Ovis). 



This fly belongs to the same order as the Horse bot fly 

 (Gastrophilus equi}. It is rather larger than the common house 

 fly, and of an ashy colour, spotted with black (Ormerod). It 

 appears in May, June, and July, and becomes an intolerable 

 nuisance to sheep. Youatt tells us " that if only one appears 

 the whole flock is in the greatest agitation." The peculiar 

 instinct of the (Estrus ovis is to deposit its eggs on the inner 

 margin of the nostril, when they soon hatch, and at once pro- 

 ceed to crawl up the nose, until they reach the recesses of the 

 frontal sinuses, where they hang on with their tentaculae until 

 the following May. 



During their passage up the nostril, and until they settle 

 themselves in their extraordinary habitation, they give great 

 annoyance to their unfortunate hosts, but after fixing them- 

 selves they do not appear to cause inconvenience or mischief. 

 Again, when they are ready to descend by the nostril, in 



