THE INSECTS 



243 



Cicada: 1, adult with wings spread, showing abdomen (Ab.), head (//.), thorax 

 (Th.) ; 2, pupal case, showing the split down the back ; 3, ventral view, showing 

 beak (.), eye (#.) 



produced by a drumlike organ which can be found just behind the last 

 pair of legs. The sound is caused by a rapid vibration of the tightly 

 stretched drumhead. The body is heavy and bulky. The wings, four in 

 number, are relatively small, but the powerful muscles give them very 

 rapid movement. The anterior wings are larger 

 than the posterior. The legs are not large nor 

 strong, the movement when crawling oeing slug- 

 gish. One of the characteristics of the cicada, 

 and of all other bugs, is that the mouth parts are 

 prolonged into & beak with which the animal first 

 makes a hole and then sucks up the juices of the 

 plants on which it lives. 



Life History. The seventeen-year cicada 

 lays her eggs in twigs of trees, and in doing this 

 causes the death of the twig. The young leave 

 the tree immediately after hatching, burrow under- 

 ground, and pass from thirteen to seventeen years 

 there, depending upon the species of cicada. In 

 the South this period is shortened. They live by 

 sucking the juices from roots. During this stage 

 they somewhat resemble the grub of the beetle 

 (June bug) in habits and appearance. When 

 they are about to molt into an adult, they climb 

 aboveground, cling to the bark of trees, and then 

 crawl out of the skin as adults. 



Aphids. The aphids are among the most in- 

 teresting of the bugs. They are familiar to all 



Maple scale, five adults and 

 many young. From pho- 

 tograph, enlarged twice, 

 by Davison. 



