DIPTERA OR TRUE FLIES. 



237 



philus equi) (slightly enlarged). 

 a, Ova, enlarged. 



The Horse-bot (Gasteophilds equi). 



Tlie Horse-bot F]y (fig. 131) is brownish-grey in colour, has 

 mottled brown wings, and appears much about the same time 

 as those just mentioned. The 

 eggs (a) are quite large objects, 

 laid on the hair of the horse 

 at the knees and shoulders. It 

 seems that at the same time 

 as the female lays her eggs she 

 places some irritating poison on 



the skin, which causes the horse fjo. i31.-hobse-bot ply (Gastm 

 to lick the spot. The warm 

 breath hatches the larva, which 

 attaches itself to the tongue and crawls down the animal's 

 throat, taking up its position in the left or cardiac portion 

 of the stomach (the white half). The 

 hots congregate here, and hold on to 

 the mucous membrane by their two- 

 hooked mandibles until mature. They 

 are pinkish -white barrel -shaped larvae, 

 with circles of spines (fig. 132, a). We 

 see them sometimes sticking round the 

 horse's anus. From six to nine months 

 are passed in the horse's stomach ; 

 when maturity is reached they pass out 

 via the intestines to the exterior in the 

 faeces, pupating in a puparium case on the 

 ground, like H. hovis and OE. ovis. 



Prevention and Treatment. — Well - 

 groomed horses seldom suffer from this 

 pest, because the eggs are detached by the " curry-comb." Farm- 

 horses in districts where G. equi is abundant should have shelter 

 from the sun during the hot part of the day ; and those in use 

 should have their knees and shoulders dressed with salt-and- 



Pio. 132.— Larva op 

 Horse-bot Flv. 



A, Horse-bot; b, end of 

 puparium ; c, spiracles at 

 anal end of bot ; d, hooked 

 mandibles. 



