ANIMAL-GALLS. 415 



indeed in the extreme, if its flesh were torn and de- 

 voured by as many large grubs ; but there is every 

 appearance that they do not at all afflict, or only afflict 

 it with little pain. For this reason cattle most covered 

 with bumps are not considered by the farmer as in- 

 jured by the presence of the fly, which generally se- 

 lects those in the best condition. 



A fly, evidently of the same family with the pre- 

 ceding, is described in Bruce's Travels, under the 

 name of zimb, as burrowing during its grub state in 

 the hides of the elephant, the rhinoceros, the camel, 

 and cattle. " It resembles," he says, " the gad-fly in 

 England, its motion being more sudden and rapid 

 than that of a bee. There is something peculiar in 

 the sound or buzzing of this insect ; it is a jarring 

 noise together with a humming, which as soon as it 

 is heard all the cattle forsake their food and run 

 wildly about the plain, till they die, worn out with 

 fatigue, fright, and hunger. I have found," he adds, 

 • some of these tubercles upon almost every elephant 

 and rhinoceros that I have seen, and attribute them 

 to this cause. When the camel is attacked by this 

 fly, his body, head, and legs break out into large 

 bosses, which swell, break, and putrefy, to the certain 

 destruction of the creature." * That camels die under 

 such symptoms, we do not doubt; but we should 

 not, without more minutely-accurate observation, 

 trace all this to the breeze-fly. 



MM. Humboldt and Bonpland discovered, in 

 South America, a species, probably of the same 

 genus, which attacks man himself. The perfect in- 

 sect is about the size of our common house-fly, 

 (Musca domestica), and the bump formed by the 

 grub, which is usually on the belly, is similar to that 

 caused by the ox-breeze-fly. It requires six months 

 to come to maturity, and if it is irritated it eats 

 * Bruce's Trareli, i. 5, and v. 191. 



