CICADA 



25 



Figure 18. — Mealy Bug. 

 One of the scale insects. 



cabbage plant. The several kinds of scale insects which 

 harm orchards may be killed by spraying the trees with a 

 solution of lime and sulphur. 



16. Cicada. — One of the most interesting insects of the 

 Hemiptera is the seventeen year cicada (si-ka/da), com- 

 monly called the " seventeen 

 year locust." The name is 

 given to it because the 

 nymphs (nim'fs, the imma- 

 ture stage) remain in the 

 ground, actively feeding on 

 roots, for seventeen years. 

 There is another kind of 

 cicada that remains in the 

 ground for thirteen years. 



Every thirteen or seven- 

 teen years, generally in the 

 month of May, the nymphs crawl out of the ground, climb 

 trees or fences, and molt into adult cicadas. The adult 

 females lay their eggs in tender shoots of trees, and this 

 causes the shoots to die. The young cicadas, after hatch- 

 ing in the shoot of the 

 tree, go into the ground 

 and begin their long 

 period of larval exist- 

 ence which lasts thirteen 

 or seventeen years. 

 These cicadas are usu- 

 ally found in limited 

 areas, but in these areas 



Figure 19. -Cicada, Adult and Nymph. are very numerous. 



The cicadas which we 

 hear every summer are another kind, whose nymph lives 

 in the ground for two years. As there are two broods 



