32 HOW TO TEACH BEETLES, BUGS. AND LOCUSTS. 
These eggs are deposited on the under surface of 
the leaves of the squash-vine. 
The eggs, larvae, pupae, and perfect insects may 
all be collected from squash vines early in the fall. 
It is then the best time to make collections. The 
larvae and pupae closely resemble the imagos in 
everything save the wings. Thus bugs are seen to 
be different from beetles in another respect, i.e., 
they do not undergo complete transformations as the 
beetles do. For this reason insects are often classi¬ 
fied as belonging to two classes: (i) Those which 
undergo complete metamorphosis, and (2) those 
which undergo incomplete metamorphosis. The 
young of the former are called larvce, those of the 
latter, nymphs. 
THE CHINCH-BUG. 
This is the enemy of our wheat crop. Vast 
quantities of this most useful grain are destroyed 
annually by this insect pest. The damage done in 
1890 is estimated at four million dollars. It is a 
small beetle not much more than one tenth of an 
inch in length. The four wings are white. There 
is a peculiar symmetrical black figure on the back. 
The female lays over 500 eggs on the ground and 
the larvae hatch out in about two weeks. They 
attack the grain, and here they may be found all 
through the summer. 
Chinch-bugs are abundant from the Atlantic coast 
to Kansas and Nebraska, and from Maine to the 
