Afr. Ci.aRk'j Ohfcrvations on the Genus Oejlrus. 313 



chryfalides of this fly, which I uniformly found under the dung of 

 horfes. They produced the flies, male and female, rcprefented at fig. 

 18 and 19; hut not having at that time any idea of writing on this 

 fubjcct, I unfortunately threw away the chryfalides. The larva I am 

 at prefcnt unacquainted with ; but if it inhabited X\\<i fauces of the 

 horfe, it would produce fuch troublefome fymptoms as could not 

 cafily efcape the notice of thofe whofe bufmefs it is to attend to the 

 difcafes of cattle. Such a difeafe has, however, never been defcrlbed 

 by any writer on this fcience; nor, after an extenfive opportunity both, 

 in the dead and living fubje6l of obferving them, have I ever feen a hot 

 in thQ fauces. Perhaps the bots of the ftomach having crawled to 

 the fauces in fearch of food might have given rife to this idea, or they 

 may even have accidentally bred there; for there is little doubt theie 

 animals can live in any part whatever of the alimentary canal. 



I am induced to fufpe£t they inhabit the ftomach, as well as the 

 two former fpecies; but of this we muft at prefent remain in un- 

 certainty, as well as of the manner in which this fpecies depofits 

 its eggs. 



I have given it the name of veterinus, becaufe beafts of burden are 

 particularly fubjeft to it, in preference to the erroneous one of tiajalis. 



Of the Oestrus Ovis. 



I PROCURED about the middle of June fome full-grown larvae of 

 the G2. Ovis, from the inficfe of the cavities of the bone which 

 fupports the horns of the fheep. See fig. 14. 



They are nearly as large as thofe of the CE.Etjut, of a delicate white 

 colour, flat on the under fide, and convex on the upper; having no 

 fpines at the divifions of the fcgments, though they arc provided; 

 with teniacula at the fmall end. The other end is truncated with a 



Vol. III. S s prominent 



