INSECT ENEMIES OF EASTERN FORESTS 505 
Figure 127.—Weork of the maple leaf cutter (Paraclemensia acerifoliella) on 
I 
sugar maple. 
feed at least two seasons. Pupation takes place in the burrow, but the 
pupa moves to the entrance hole prior to the emergence of the adult. 
In the genus Sthenopis, the larvae, so far as known, bore in the roots 
of trees and shrubs growing in wet ground, and they are able to work 
below the water level. Sthenopis argenteomaculatus (Harr.) works 
in the base of the trunk and roots of alder, and S. thule (Stkr.) in 
the roots of willow. Both species range through most of the North- 
eastern States. Their work seldom attracts attention. 
THE FLIES 
Orver DIPTERA 
By R. T. WEBBER 
The Diptera, commonly referred to as flies, are readily recognized 
by a single pair of functional wings, the hind wings being reduced to 
mere knobs called halteres. A few species, however, are wingless. 
