no 



The Horse Bot Fly. 



[may, 



a gentle heat, the larva typically and usually assumed the posi- 

 tion of that in Fig. i. It is therefore quite possible that some or 

 many of the larvae are licked up by the tongue of the horse 

 without entirely leaving the egg. The stomach figured in the 

 other photograph was obtained from the slaughter-house at 

 Aberdeen. It shows not only the bots in situ, but the pitted 

 thickened regions formed at the point of attachment. 



It is rather remarkable that although a species of Gastrophilus 

 is again very common in the middle and South of England, bots 

 are'altogether absent from the most northern portion of Eng- 

 land, at all events, apparently, from Northumberland and 

 Durham. The larvae are only seen in those counties in horses 



Fig. 2. — Bots attached to the Stomach of a Horse. 



and ponies imported from regions where the insect naturally 

 occurs. In spite of the fact that the larvae are thus constantly 

 introduced, for some reason not at all apparent none of the 

 species manages to establish itself. A case has been reported, 

 however, in which the larvae appeared during the succeeding 

 season in such an imported animal, but without any other horse 

 being affected either then or subsequently. 



It would be interesting to know what species actually do occur 

 in the British Islands, and further observations are necessary as 

 to the behaviour of the horse when the insect is ovipositing. 

 In Aberdeenshire, so far as could be gathered, the horse does 

 not appear to take any notice of the proceeding. Continental 



