40 MISC. PUBLICATION 318,:U. S. DEPT. OF AGRICULTURE 
of oatmeal, white arsenic, sugar, salt, and water is one method of 
control. DDT or chlordane sprays or dust are preferred for treatment. 
Caddisflies.—A long streams where the water flows rather swiftly, 
one finds small mothlike insects of pale-brown color with wings folded 
rooflike over their backs. ‘These are the caddisflies. Unlike those of 
the moths, the two pairs of wings are 
scaleless and usually sore or less 
clothed with long, silky hairs. The 
adults take very little food, but many 
accept sweet fluids to a certain extent. 
They fly readily. The larvae crawl or 
swim in water and feed on water forms 
of either plant or animal life. They 
winter as larvae, usually in streams. 
Their hfe changes are complete. The 
caddisfly shown here is about three-fourths of an inch long with a 
wing expanse of about 114 inches. A sketch of the caddisfly, ap- 
pearing in the section on collections and identification, order Tri- 
choptera, part III of this manual, gives an idea of the position of the 
wings when at rest. The scientific name of this insect is Pyenopsyche 
subfasciatus. 
Stone flies—There is another group of insects that live around 
rapid streams and wave-washed, rocky shores. This is the stone fly 
group, which. belongs to the order Plecoptera. 
These insects range from °4 to 114 inches in 
length, are pale brown, and the wings are 
folded flat over the back. They have chewing 
mouth parts, but the adults feed very lhttle; 
the nymphs feed mainly on insects in the fast- 
flowing streams. The adults fly readily, but _  _ —S—=—ssS 
the nymphs crawl and swim in the water.  ficure 102—Stone fiy. 
The stone fly winters as a nymph in water 
leading to large rivers. The life changes are incomplete. The 
nymphs may serve as fish food. The species shown here is Acro- 
neuria abnormes. 
aeraeamnee eee SiS = F Soon A 
Z i 
* 4 
FIGuRE 101.—Caddisfly. 
Pe ee ee ee 
