PARASITOLOGY. 29 
Lite Cycle.—The fly is viviparous, and attacks the 
sheep and goats from June to October, but only in 
the warmer part of the day. It deposits its larvae 
in the anterior nares. The larva is provided with 
two hooklets, by means of which it gradually works 
its way to the frontal sinuses, where it passes the 
larval stage, which requires ten months. It then 
passes out to the ground, burrows into the ground 
and there passes through the pupal stage, which lasts 
from four to six weeks. 
Animals Attacked.—Sheep and goats. 
Parts Intested.—Frontal sinuses and turbinated 
bones of the head. 
Condition Produced.—The sheep, hearing the noise 
of the fly, runs, thrusts its nose into the ground or 
amongst other sheep, and strikes at its nose with its 
feet in an effort to rid itself of the pest, which, slug- 
gish at other times, now flies at the nostrils with 
great rapidity. The larvae work their way to the 
frontal sinuses by means of hooklets and contractility 
of the body. In the frontal sinuses they attach 
themselves, by means of two hooklets, to the mucous 
membrane. If only three or four are present in 
the sinuses they do not produce much disturbance,— 
a slight catarrhal discharge of a muco-purulent na- 
ture. When many are present there is noted a pro- 
fuse muco-purulent discharge from the nostrils, loss 
of appetite, frequent coughing and sneezing, slow, 
weak gait, and tossing of the head. The animal 
becomes too weak to rise, and finally dies. 
Treatment.—Trephine and remove larvae with for- 
‘ceps. 
Prophylactic Treatment.—The nose may be smeared 
