GREAT CRANE-FLY—GAD AND BOT FLIES. 561 
tion to its size. This property it enjoys in common with many other insects, 
among which the Common Grasshopper, the Frog-hopper, and the Halticas, 
or Turnip-flies, are conspicuous. In all these insects the hinder pair of legs 
are very long and powertul. 
DIPTERA. 
WE now pass to the DIPTERA; or Two-winged Insects, which may be 
known not only by the single pair of wings, but by the little appendages at 
their base, called halteres, or balancers, and which are the only vestiges of 
the hinder pair of wings. Moreover, the wings are not capable of being 
folded. This order is of vast extent, and includes a whole host of species. 
THE Tipulide are very familiarto us through the well-known insects called 
DappDy LONG-LEGS, or CRANE-FLIES, one of which is here represented. In 
their perfect state these insects are perfectly harmless, although ignorant 
people are afraid to touch them. But in thei: larval condition they are_fear- 
ful pests, living just below the surface of the ground, and feeding on the roots 
of grasses. Whole acres of grass have been destroyed by these larve ; and 
GREAT CRANE-FLY.—( Zipula gigantea.) 
some years ago Blackheath Park was so infested with them, that in the 
beginning of autumn the ground was covered thickly with the empty pupa 
cases of the escaped insect. 
GAD AND BOT FLIES, 
The left-hand figure in the illustration represents the common BREEZE- 
FLY, a well-known British example of the Tabanide. It is also known 
by the popular names of GaD-FLyY and CLEG, As in the gnats, the 
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