Tower-Building Cicada. 



97 



SEVENTEEN-YEAR CICADA. 

 Adult, Chrysalis-Case, Pupa, Entrances to Burrows and Egg- Nests. 



females may be seen preparing nests for the reception of 

 their eggs. Branches of moderate size are selected for this 

 purpose. Their manner of perforation is curious and inter- 

 esting. Clasping the branch on both sides with their legs, 

 and bending the ovipositor at an angle of forty-five degrees, 

 they repeatedly thrust it into the bark and wood in the 

 direction of the fibres, at the same time setting the lateral 

 saws at work, thereby detaching little splinters of wood at 

 one end, which are intended to serve as a kind of fibrous 

 cover for the nest. The hole is bored obliquely to the pith, 

 and by a repetition of the same operation is gradually 

 enlarged until is formed a longitudinal fissure of sufficient 



