302 INSECTS AND OTHER SMALL ANIMALS 



animals, Some have their wings thickened at the base, 

 the outer portion being membranous. This gives the 

 name Hemiptera. Still other members of this order 

 have two regular wings, and others have no wings 

 at all. 



Many bugs emit a very disagreeable odor. Their 

 metamorphosis is incomplete, there being no quiet 

 pupa stage. 



This order includes the cicada, or so-called " locust," 

 also the seventeen-year locust that makes a sound that 

 we are all familiar with in the hot dog days, hence it is 

 often called the dog-day harvest fly; lice, infesting 

 both plants and animals; scales; bedbugs; leaf 

 hoppers ; chinch bugs ; squash bugs ; skippers ; and 

 many others. 



Plant Lice (Aphides). These may be found on all 

 parts of plants, where they often do great damage by 

 sucking the juices. They are usually more or less 

 pear-shaped, green, white, or gray in color. They are 

 held in check under ordinary conditions by their 

 enemies. One of these, a parasitic, four-winged fly, 

 lays its eggs under the skin of the insect, eventually 

 eating out the insides, and another, the lady bug, 

 devours great quantities of the lice. When their na- 

 tural enemies are for any reason reduced in numbers, 

 the aphides become a great pest. The green bug that 

 did such great damage in the summer of 1906 was a 

 plant louse that developed in numbers sufficient to 

 destroy the small grain crop in some sections of the 

 country. Nearly every plant has some species of 

 plant louse infesting it. Some are on the leaves, some 

 on the stem, and others make galls on the roots of the 

 orchard trees and of grape vines. Plant lice may be 



