Mr. CtARK*/ Obfervaltons on the Genus Oejrus, 311 



The teafing of other flics will fometimes occafion a motion of the 

 head fimilar to this; but it ihould not be niiftaken for it, as it is 

 never in any degree fo violent as during the attack of the Oejlrus. 



At other times this Oejirus gets between the fore-legs of the horfe 

 whilfl he is grazing, and thus makes its attack on the lower lip : 

 the titillation occafions the horfe to ftamp violently with his fore- 

 foot againfl: the ground, and often ftrike with bis foot as though 

 aiming a blow at the fly. They alfo fometimes hide themfelves in 

 the grafs ; and as the horfe ftoops toi graze they dart on the mouth 

 or lips, and are always obferved to poife themfelves during a few 

 feconds in the air, while the egg is preparing on the point of the 

 abdomen. 



When feveral of thefe flies are confined in a clofe place, they 

 have a particularly flrong fufty fmell ; and I have obferved both 

 fhcep and horfes, when teafed by them, to look into the grafs and 

 fmell to it very anxioufly ; and if they by thefe means difcover the 

 fly, they immediately turn afide and haften to a diftant part of the 

 field. 



The eggs of this fpecies appear of a darker colour than the for« 

 mer, and the circumftauces attending their pafTage to the flomacli 

 .1 am unacquainted with. 



The larva of the CE. hamorrhoidaUt^ as well as the former fpecies, 

 appears to have been termed among the Romans, Cojus *, which 

 feems to have been a general expreffion for any kind of foft imper- 

 fedl animal, and to have been very analogous, and as extenfively 

 applied as the word grub is at prefent in the Englifh language. 



The learned Charlton (Onomajlicon Zo'icon, p. 56), and afterwards- 

 Dr. Johnfon (fee Diftionary), have confidered afcarides as the fyno- 



• Vide Flovius Vegetius Rtnatut di Arte Vetmttariay^, 6a, 64, 69, td, Manh, 



nymous 



