26 LKS^ONS IN ACiKK ULTURE 



stage, but grow their wings as they hop about in search 

 of food. 



Feeding habits of insects. Insects may be divided 

 into two classes, according to their habits of injury to 

 plants: the leaf-eating insects and the sap-sucking in- 

 sects. These habits of the insects furnish the farmer a 

 clue to methods of destroying them. If he finds that 

 a certain insect is eating the leaves of his plants, he 

 can spray them with a poison, such as lead arsenate, 

 and the insects will eat the poison and die. If the 

 insect that is injuring the plants has a beak which it 

 uses to suck the sap from the tree or plant, without 

 eating the leaves, then the farmer can spray with lime- 

 sulphur or a mixture of kerosene and soapsuds, which 

 will stop the insect's breathing pores or destroy its 

 body. Directions for making these mixtures are given 

 elsewhere in this book. 



The body of insects. Insects are so called because 

 they are "in sections." There are three main sec- 

 tions of an insect's body the head, thorax, and abdo- 

 men. The head is provided with a pair of feelers, a 

 pair of strong jaws (or a sucking tube), and two com- 

 pound or two simple eyes. Three pairs of legs and 

 usually two pairs of wings are attached to the thorax. 

 The abdomen is the back part of the body, made up of 

 segments. Insects breathe through little holes in their 

 sides. In the practical exercises which follow you will 

 note all these points of structures in various insects. 



NOTE. The practical exercises on insects will be 

 given as separate lessons and so numbered. 



