464 
GAD-FLY. 
any alternative, or means of avoiding this, though a 
hostile band was in their way, capable of spoiling 
them of half their substance.” 
These insects are said by Mr. Bruce to inhabit 
only one species of soil, which is a black fat earth, 
of extraordinary fertility, which seems from the 
first to have given a law to the settlement of the 
country, as it deprived those inhabitants of the 
fat earth called mazaga, brought up in caves and 
mountains, from enjoying the assistance of any 
beasts of carriage. “ It deprived them of their flesh 
and milk for food, and gave rise to another nation 
whose manners were just the reverse of the first. 
These were the shepherds, leading a wandering life, 
and preserving these immense herds of cattle by 
conducting them into the sands beyond the limits 
of the black earth, and bringing them back again 
when the danger from the insect was over.” 
The jarring noise which the zimb makes in its 
flight, is supposed by Mr. Bruce to proceed partly 
from the vibration of the three hairs at the snout : 
he observes that it flies with more rapidity than the 
bee, and that its motion resembles that of the Eng- 
lish gad-fly. In its manners it certainly bears a 
strong resemblance to that insect, and appears to de- 
serve a place in the same genus. 
