122 ANIMAL FORMS 
attracted by lights, and have come to be called “electric- 
light bugs.” 
Among our most dreaded insect pests are the chinch- 
bugs—small black-and-white insects, but traveling in com- 
: panies aggregating many millions. 
As they go they feed upon the 
stems and leaves of grain, which 
_ they devour with extraordinary ra- 
pidity. The squash-bug family is 
also extensive, and destructive to 
the young squash and pumpkin 
plants in the early spring. 
The lice are small, curiously 
shaped bugs, which suck the blood 
of other animals. The plant-lice, 
also small, suck the juices of 
plants, and are often exceedingly 
destructive. This is especially true 
= of the phylloxera, a plant-louse 
Fic. “4.—Giant water-bug (Ser- which causes annually the loss of 
phus dilatatus), with eggs at- ae ss 
tached. millions of dollars among the vine- 
yards of this and other countries. 
Even more destructive are the scale-insects, curiously mod- 
ified forms, of which the wingless females may be found on 
almost any fruit-tree and on the plants in conservatories, 
their bodies covered with a downy, waxy, or other kind of 
covering, beneath which they remain and lay their eggs. 
119. The flies (Diptera)—The group of the Diptera 
(meaning two-winged) includes the gnats, mosquitoes, fleas, 
house-flies, horse-flies (Fig. 75), and a vast company of 
related forms. Only a single pair of wings is present, the 
second pair being rudimentary or fashioned into short, 
thread-like appendages known as balancers, though they 
probably act as sensory organs and are not directly con- 
cerned with flight. The mouth-parts are adapted for pier- 
cing and sucking. The eyes, constructed on the same plan 
