■THE gad ylt . 
5*7 
Genus I. — Qejlrus . The Gad Fly. 
This infe& has no mouth, nor any vifible probofcis : in 
place of thefe are three fmall points. Upon the head, 
there are three ftemmata, or fmall eyes ; the antennae are 
fetaceous, and commonly lhort. 
Oefter bovinus, the ox gad fly. This large fpecies pe- 
netrates through the tkin of cattle, and depofits its eggs 
there. It has no mouth, black eyes, a yellow thorax, 
and pale-coloured feet ; the wings are membranous, and 
interfperfed with fmall black fpots *. 
Oeftrus rangiferus. This fpecies frequents the backs 
of rein-deer, cfpecially thofe that are tamed, and depolits 
its eggs there ; it is twice tlie fize of the former, and cal- 
led by the Laplanders curbma f. The wings are with- 
out fpots, and the body is covered with a yellowifh 
down. 
Oeflrus ovis, lodges in the nofes of ruminating animals, 
particularly of the Iheep, and is therefore called by the 
Swedes, noofmaliken %. To this tribe is alfo added the 
ceflrus hsemorrlioidalis, which makes its way into the 
anus of the horfe, in order to depofit its young j- 
In the economy of nature, there is nothing appears 
more furprifing than that inftin£l by which certain ani- 
mals are directed to depofit their young in the only place 
x where 
* Rai Inf. p. 371, & Derham’a Phyfico Theol. 1 . 8. c. 6. 
f Fauna Suec. N. 1035. | Reaumur, Tome IV. 
§ Voyage de Gotlande, 277. 
