30 HOW TO TEACH BEETLES, BUGS, AND LOCUSTS. 
pair of wings when not in use. In the bug the first 
pair of wings is membranous, and when at rest they 
are folded back so that their tips overlap. 
2. The second pair of wings also vary. In the 
beetle these perform the true act of flight. They 
are much larger than the first pair. In the bug, 
however, this second pair is much smaller, being 
about half the size of the front pair. Hence the 
name, Hemiptera, as applied to this order of insects. 
3. The mouth-parts are also very different. In 
beetles these are fitted for biting, hence the parts— 
mandibles, maxillae, etc. ; but in bugs the mouth- 
Fig. 16.—Types of Bugs. 
parts have become fused together into a tube or 
proboscis suited for piercing and sucking juices 
from plants and animals. As the “ June-bug” or 
May-beetle is a common type of beetle, so the 
squash-bug may be taken as a type of bug. Let 
specimens of these be collected for study and com¬ 
parison. 
There are several classes of bugs; but it is our 
intention to devote our studies to a few of the more 
familiar species. 
