JULY 143 



to emerge. He creeps out and up the tree 

 until he finds a place into which he can 

 clinch his toes. Then his back splits open, 

 and the adult form, tender and limp, 

 squirms out and later hardens into the per- 

 fect insect. 



Ever since 1715 (and how often before 

 that no one knows) a brood of cicadas has 

 been reappearing every seventeen years in 

 the southeastern part of Pennsylvania and 

 over much of New Jersey, Delaware, and 

 Maryland. 



In 1902 they returned in great abun- 

 dance, but by this time practically all super- 

 stition was gone in the matter, and the only 

 fear people had was that the insects might 

 do serious damage to trees. But even this 

 dread proved unnecessary, and practically 

 no harm resulted from their visit. Mean- 

 while the increase of general knowledge on 

 the subject was so great that probably no 

 brood of insects has ever been so intelli- 

 gently watched by so many curious eyes 

 as greeted the last brood of this long-known 

 series. 



