O'l'HER MEMBERS OF THE CLASS — IN8Ef:'l\\ 177 



the squash bug (Fig. 117). There are seven or eight gener- 

 ations of this bug during a season in the South. 



The cicadas. —Tire seventeen-year cicada, improperly 

 called locust, lays its eggs in slits made in twigs. The 

 young hatch in about six weeks and enter the ground, 

 where they live on the soil humus and sap of the tree 

 roots for nearly seventeen }-ears. In the si)ring of the 



I'lo. lis. — Sevexiteea-year cicada. 



seventeenth year, the nymphs come out of the ground, ' 

 crawl up the trunk of the tree, where the skin bursts open 

 on the back, and the adults (Fig. 118) pull themselves out, 

 leaving the empty nymph skins clinging to the tree. In 

 the South these cicadas live thirteen }'ears in the earth. 

 The dog-day harvest fly (Fig. 119) is the insect responsible 

 for the high, sharp trilling that comes to us in the hot 

 summer days from the trees where the singer lies hidden. 

 It takes this cicada only two years to develop, and, since 

 there are two broods, the adults appear every year. 



That large group of insects known as the scale insects 

 belongs to the same order as the bugs and cicadas. These 

 are small, louselike insects which, in many cases but not all, 

 secrete a hard, waxy covering, or scale, over the body 



IIF.RRICK S ZOOL. 



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