THE GAD-FLY, WURBLES. OR WORMALS. 525 
points, (plate x. fig. 12,) somewhat like the claw of a cat. 
The two shorter pieces are also pointed, but not curved ; 
and by the union of the five, a tube is composed for the 
passage of the eggs. (See plate x. fig. 11.) It would be ne¬ 
cessary, Reaumur confesses, to see the fly employ this instru¬ 
ment to ascertain in what manner it acts, though he is dis¬ 
posed to consider it fit for boring through the hides of cattle. 
Mr. Bracey Clarke, taking another view of the subject, 
is decidedly of opinion that the fly does not pierce the 
skin of cattle with its ovipositor at all, but merely glues its 
eggs to the hairs, while the grubs, when hatched, eat their 
way under the skin. If this be the fact, as is not improba¬ 
ble, the three curved pieces of the ovipositor, instead of 
acting, as Reaumur imagined, like a centre-bit, will only serve 
to prevent the eggs from falling till they are firmly glued to 
the hair, the opening formed by the two shorter points per¬ 
mitting this to be effected. 
The extraordinary effects produced upon cattle, on the 
appearance of one of these flies, would certainly lead us to 
conclude that the pain inflicted by the ovipositor, is excru¬ 
ciating. Most of our readers may recollect to have seen, 
in the summer months, a whole herd of cattle start off 
across a field, at full gallop, as if they were racing, their 
movements indescribably awkward—their tails being poked 
out strait and stiff behind them, and their necks stretched 
forward to their utmost length. All this consternation has 
been known from the earliest times to be caused by the 
appearance of the gad-fly. 
If Mr. Clarke’s views be correct, when the egg of the ox- 
fly is hatched, the grub (plate x. fig. 17) immediately bur¬ 
rows under the skin, where it feeds upon the fatty matter, 
and remains until it has reached maturity. As the grub 
continues to grow, the bumps, or wurbles, increase in dimen- 
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