THE GAD-FLY, WURBLES, OR WORAEALS. 525 



points, (plate x. fig. 12,) somewhat like tlie claw of a cat. 

 The two shorter pieces are also pointed, but not curved ; 

 and bj 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. 1 7) 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- 



