158 INSECTA. 
ORDER VII. 
HEMIPTERA*. 
The Hemiptera, according to our system, terminate the numerous 
division of Insects which are provided with elytra, and of all those, 
are the only ones which have neither mandibles nor maxille properly 
socalled. A tubular, articulated, cylindrical, or conical appendage 
curved inferiorly, or directed along the pectus, having the appearance 
of a kind of rostrum, presents along its superior surface, when raised, 
a groove or canal from which may be protruded three rigid, scaly, 
extremely fine, and pointed sete, covered at base by a ligula. These 
setee, when united, form a sucker resembling a sting, sheathed in the 
tubular apparatus we have just described, where it is kept in situ by 
the superior ligula placed at its base. The inferior seta consists of 
two filaments, which are united into one atalittle distance from their 
origin, so that in reality the sucker is composed of four pieces. The 
inference drawn from this by M. Savigny is, that the two superior 
setee, or those which are separate, represent the mandibles of the tri- 
turating Insects, and that the two filaments of the inferior seta cor- 
respond to their maxille +; this once admitted, the labium is replaced 
by the sheath of the sucker, and the triangular piece at the base be- 
comes a labium. A true ligula also exists, and under a form analo- 
gous to that of the preceding piece, but bifid at the extremity. The 
palpi are the only parts which have totally disappeared: vestiges of 
them, however, may be perceived in Thrips. 
The mouth of Hemipterous Insects is then only adapted for extract- 
ing fluids by suction; the attenuated stylets of which the sucker is 
formed, pierce the vessels of plants and animals, and the nutritious 
fluid being successively compressed, is forced into the internal canal, 
and thus arrives at the esophagus. The sheath of this apparatus is at 
these times frequently bent into an angle, or becomes geniculate. 
These Insects, like other Suctoria, are furnished with salivary vessels ig 
In most of the Insects which compose this order, the elytra are co- 
riaceous or crustaceous, the posterior extremity being membranous 
and forming a sort of an appendage to them; they almost always 
decussate ; those of the other Hemiptera are simply thicker and larger 
* Ryngota, Fab. 
+ Or rather, in my opinion, to their terminal lobe, or that superior portion which 
in the Bees and Lepidoptera is prolonged into a thread or attenuated lamina, and 
reaches beyond the insertion of the palpi. 
+ See in particular the anatomical observations of M. Leon Dufour, on the Cicade 
and Nepe. 
ae 
