250 



AGRICULTURE 



the grasshoppers and the true bugs. Those who study 

 insects use the name "bug" only for a certain large group 

 of insects, just as one would speak of the "flies," "bees," 

 and "grasshoppers." Grasshoppers and bugs have the 

 same general form of body when young, but acquire 

 wings as they become adult. Most of the other common 

 insects undergo very remarkable changes. It is important 

 to know this, since it may be very difficult to destroy an 

 insect in one stage, but very easy to do so in another. 

 Among those that make great changes in form are all of 

 the caterpillars, which become butterflies or moths when 

 full grown; the maggots, 

 which become flies ; the 

 grubs , which become beetles. 

 You will find it exceedingly 

 interesting to watch a cater- 

 pillar change its skin or the 

 butterfly emerge from its 

 chrysalis or pupal case. 



FIG. 165. FOUR STACKS OF INSECT (TENT CATERPILLAR). EGGS SEPARATED 



AND MAGNIFIED 

 Larva; cocoons; moth. 



Stages in an insect's life. In the life of most insects 

 there are four well-defined stages. The first is the egg, the 

 second is the larva, the third is the pupa, and the fourth 



