196 ELEMENTS OF COMPARATIVE ZOOLOGY. 



themselves, killing them before they have had time to 

 ripen the grain. 



The squash-bug, which does such damage to pumpkin- and 

 squash-vines, is another form of Heteropteran, as are those 

 familiar forms which have no other common name than 

 "stink-bug." No one who has ever taken into his mouth 

 a berry over which one of these animals has travelled can 



Ci 



FIG. 83. Seventeen-year locust (Cicada septendecim). From Riley. a. 

 pupa ; b.pupa-case from which the adult, c, has escaped ; d, twig bored 

 for the deposition of eggs. 



doubt the appropriateness of the name. However, these 

 bugs are not alone in their malodorous qualities; many 

 others, like the squash-bug and bedbug, also secrete a 

 strong-smelling fluid, which of course protects them from 

 birds and other insect-eating animals. 



Among the Homopteran forms the cicadas come first. 

 One of these, the " dog-day locust" (it is not a locust at 

 all), is familiar from its shrill note heard during the hottest 



