IIEMIPTERA. 179 



raising tv^J^o large valves beneath the belly, and which arc 

 separated from each other by thin partitions having the trans- 

 parency and brilliancy of mica or of thin and highly polished 

 glass, tend to increase the vibrations of the sounds, and add 

 greatly to their intensity. In most of our species of Cicada^ 

 the drums are not visible on the outside of the body, but are 

 covered by convex triangular pieces on each side of the first 

 ring behind the thorax, which must be cut away in order to 

 expose them. On raising the large valves of the belly, how- 

 ever, tliere is seen, close to each side of the body, a little 

 opening, like a pocket, in which the drum is lodged, and from 

 which the sound issues when the insect opens the valves. 

 The hinder extremity of the body of the female is conical, 

 and the under side has a longitudinal channel for the reception 

 of the piercer, which is furthermore protected by four short 

 grooved pieces fixed in the sides of the channel. The piercer 

 itself consists of three parts in close contact with each other; 

 namely, two outer ones grooved on the inside and enlarged at 

 the tips, which externally are beset with small teeth like a 

 saw, and a central, spear-pointed borer, which plays between 

 the other two. Thus this instrument has the power and does 

 the work both of an awl and of a double-edged saw, or rather 

 of two key-hole saws cutting opposite to each other. No 

 species of Cicada possesses the power of leaping. The legs 

 are rather short, and the anterior thighs are armed beneath 

 with two stout spines. 



The duration of life in winged insects is comparatively very 

 short, seldom exceeding two or three weeks in extent, and in 

 many is limited to the same number of days or hours. To 

 increase and multiply is their principal business in this period 

 of their existence, if not the only one, and the natural term of 

 their life ends when this is accomplished. In their previous 

 states, however, they often pass a much longer time, the length 

 of which depends, in great measure, upon the nature and 

 abundance of their food. Thus maggots, which subsist upon 

 decaying animal or vegetable matter, come more quickly to 

 their growth than caterpillars and other insects which devour 

 living plants ; the former are appointed to remove an offensive 



