THE GAD FLT. 517 



Genus I. — Oefirus» The Gad Fly, 



J/Hts infe6l has no mouth, nor anj vifible probofcis : In 

 place of thefe are three fmall points. Upon the head, 

 there are three {lemmata, or fmall ejes ; the antennae are 

 fetaceous, and commonly fhort. 



Oefter bovlnus, the ox gad fly. This large fpecies pe- 

 netrates through the ikin of cattle, and depofits its eggs 

 there. It has no mouth, black eyes, a yellotv thorax, 

 and pale-coloured feet ; the wings are membranous, and 

 interfperfed with fmall black fpots *. 



Oeflrus rangiferus. This fpecies frequents the backs 

 of rein-deer, efpecially thofe that are tamed, and depofits 

 its eggs there ; it is twice the fize of the former, and c 1- 

 led by the Laplanders cur'oma f . The wings are with* 

 out fpots, and the body is covered with a yeilowilh 

 down. 



Oeftrus ovis, lodges in the nofes of ruminating animals, 

 particularly of the fheep, and is therefore called by the 

 Swedes, noofmallken J. To this tribe is alfo added the 

 ceftrus haemorrhoidalis, which makes its way into the 

 anus of the horfe, in order to depofit its young §. 



In the economy of nature, there is nothing appears 

 more furpriling than that inftincl by which certam ani- 

 mals are diredled to depoUt their young in the only place 

 I where 



• Rai Inf. p. 371, & Derham's Phyfico Thcol. 1. 8. c. 6. 

 t Fauna Suec. N. 1035. J Reaumur, Feme IV. 



S Voyage de Gotlanue, %';j. 



