220 PRODUCTIVE FARMING 



CHAPTER XX. 

 INSECTS. 



FARMERS, market gardeners, and fruit growers have their 

 enemies to combat. Their crops and animals are attacked 

 by numerous species of insects. It is estimated that hun- 

 dreds of millions of dollars are lost by the American farmers 

 annually from this cause. Fruit that is infested or deformed 

 by insects will bring much lower prices than first-class fruit. 



Structure. Insects are six-legged animals with the body 

 made up of segments or covered with a series of rings. There 

 are two pairs of wings, except that flies and mosquitoes have 

 only one pair, and in a few species of all orders the wings 

 are undeveloped or are entirely wanting, as in the case of 

 the bedbug. All insects in the adult stage have the body 

 divided into three parts: the head, the thorax, and the abdo- 

 men. The head bears the mouth parts, the antennae, or 

 feelers, and the eyes. The thorax, or chest, bears the wings 

 and three pairs of legs. See Fig. 122d. 



Many insects have enormous powers of flight, as in the 

 cases of the dragon fly and the honey bee. The Rocky 

 Mountain locust is a migrating insect and probably flies a 

 hundred miles or more at a single flight. Some of the larger 

 beetles seldom fly very far at a time. 



How Insects Feed. The mouth parts of insects are of 

 two kinds: those fitted for biting, as in grasshoppers and 

 beetles, and those suited for sucking the food, as in mos- 

 quitoes, bedbugs, bees, butterflies, and others. 



Those with biting mouth parts have two pairs of jaws 

 with which they cut and chew their food (Fig. 138). They 

 consume the entire substance on which they feed, as bark, 

 leaves, fruit, flowers, or other tissues (Fig. 121). Such insects, 

 when found on the outside of plants, may be killed by the 



