204 INSECTS 
ground and remain out of sight the next 16 years. In the 
southern states the warmer temperature hastens the de- 
velopment, and the life cycle is completed in thirteen years 
instead of seventeen. 
Other well-known pests belonging to this class are the 
true bugs (the chinch bug, squash bug, and bed bug) and 
the several kinds of lice that live as parasites on man and 
other mammals and suck their blood. But bird lice, common 
on poultry and other birds, are quite different. These have 
mouth parts for biting and eat the feathers, hair, or skin 
of their victim. 
Butterflies and Moths. — This class of insects is distin- 
guished by the fine, overlapping scales which cover the four 
ReEsTING PosITIon 
a, Butterfly; 6, Moth with wings folded around the body; c, Moth with 
wings held straight out from sides. 
wings. These scales appear like powder when they come off 
on our fingers as we touch the insect. The mouth parts of 
the adults are formed for sucking, but the larve eat solid 
food. Many of the moths are usually called “ millers,” 
especially those that fly about lights at night. 
Moths and butterflies are distinguished from each other 
as follows: 
