

LI. 
HEMIPTERA. 
THE Hemiptera are particularly distinguished from other kinds of 
insects by the form of their mouth, which consists of a beak, more 
or less long, composed of six parts, that 1s, of a lower lip or 
sheath, four internal threads, representing the mandibles and jaws 
of the grinding insects, and which are the perforating parts of the 
beak, and, lastly, of the upper lip or labrum. Owing to this 
apparatus these insects are essentially sucking ones, and chiefly 
nourish themselves with the juice of vegetables, which they draw 
up with their beak. The wings of the Hemiptera are usually four 
in number; sometimes altogether membraneous and similar to 
each other. Sometimes the upper ones being of rather harder con- 
sistency than the lower ones. In general, the former are quite 
different from the lower wings, and are only membraneous at the 
tip, whereas the other part is thick, tough, and coriaceous. | 
The Hemiptera are divided into two very distinct sections. The 
one is composed of insects whose beak grows from the forehead or 
upper part of the head, ana of which the elytra* are half coria- 
ceous and half membraneous, having the base of a different texture 
from the extremity; these are the Heteroptera (érepoc, different, 
repov, wing). The other section is composed of those whose beak 
grows from the lower part of the head, and of which the elytra 
have always the same consistency ; these are the Homoptera (60s, 
the same). We are about to give the history of these two sub- 
orders. 
* The upper wings of Hemiptera, Orthoptera, and Coleoptera.— Ep. 
