DIPTERA. 
i 
117 
and become pupa). These larva) do not make their way 
to the brain and cause the death of the poor sheep, as is 
often asserted. Sheep may often be seen in hot weather 
shaking their heads and holding their noses close to the 
ground in dry dusty spots, in order to prevent the gad¬ 
fly entering the nostrils. 
The Horse Bot-fly ( Gasterophiliis equi ) deposits its 
eggs on the hairs of such parts of the body as the horse 
can reach with its tongue ; these parts being licked by 
the horse, the attached eggs—little yellow specs, familiar 
to all—are conveyed to the stomach, where the larva) 
are developed ; when full grown the larva detaches 
itself and discharged by the horse falls to the ground, 
where the final changes are undergone. It is curious 
to see this Bot-fly in the act of laying its eggs on the 
horse's skin ; it will remain for a few seconds opposite 
a spot in the horse, hawk-like—the wings vibrating with 
amazing rapidity—and then, with its pointed abdomen, 
affix an egg to the hair; then the process will be re¬ 
peated. 
The sub-section— Hypocera —in which the antenna) 
are situated low down near the mouth, consists of the 
genus Phora only, which contains a few minute flies, 
which need not detain us at all. 
The Eproboscidea, the second section of the Diptera, 
contain insects which are parasitic in various quadrupeds 
and birds, such as the Forest-fly ( Uippobosca :), the 
Sheep-tick ■(. Melopliagus ovinus ), the Bird-tick ( Ornitho - 
myia avicularia ), the Swallow-tick (Stenopterix Hirun - 
dims), and the Bat-tick ( Nycteribia ). 
