542 
AETICULATA. 
more or less spherical form, sometimes oval or kidney-shaped, and in a few cases divided into 
two parts by an elevated ridge, so that the insect appears to have four eyes ; while in a few 
beetles, inhabiting caves or other subterranean situations, the eyes are entirely wanting. 
The thoracic segments are always distinctly separated. The prothorax is usually of consider- 
able size, and bears the first pair of legs. The mesothorax and metathorax bear the other two 
pairs of legs and the elytra and 
w;ings, beneath which their up- 
per surface is entirely concealed, 
with the exception of a small 
triangular piece of the meso- 
thorax — the scutellum — which 
is usually visible at the base of 
the suture. The elytra gener- 
ally cover the entire dorsal sur- 
face of the body to the apex of 
the abdomen, and the upper 
portion of these segments is 
then of a soft and somewhat 
membraneous texture ; but in 
some cases the elytra are short, 
leaving a greater or less portion 
of the abdomen uncovered ; 
this is then equally homy on 
both surfaces. In some cases 
the wings are wanting, when 
the elytra are not unfrequently 
completely soldered together. 
HERCULES BEETLE. 
The legs are usually constructed exclusively for walking; but in some cases the fore-legs are con- 
verted into fossorial organs, and in others the hind-legs are flattened for swimming, or furnished 
with thickened thighs for saltatorial purposes. The tarsi are genei'ally com2DOsed of five joints, 
and this appears to be the normal number. The number varies, however, in different groups 
from two to five. 
The metamorphosis of the Coleoptera is complete ; the larva is usually a soft fleshy grub, 
although the texture of its integuments is often leathery, or even somewhat horny, especially in 
the rapacious species. The soft larvse are almost always furnished with a horny head, armed 
with distinct jaws, and usually furnished mth simple eyes. They are generally furnished with 
six thoracic legs, although these are sometimes wanting, and frequently also with anal pro-legs. 
The pupae are free and quiescent. 
We shall notice the insects of this order under tlia following subdivisions: the Pentamera, 
the Heteroniera, Tetramera, and Trimera. 
THE PEOTAMERA. 
This term, derived from the GvQok pente^ five, and mera, divisions, is applied to the insects of 
this group, as most of the species have their tarsi composed of five distinct joints; they are, 
however, very numerous, and there are great variations in structure. 
THE aEODEPHAGA. 
This term signifies Ground-Beetles, and is descriptive of the tribe. They are exceedingly 
active, and often beautiful insects ; generally nocturnal in their habits, concealing themselves 
during the day under stones and in holes in the ground. The larvae are elongated, flattened, and 
usually covered with a horny integument. In their predaceous habits they resemble the perfect 
insects.- 
The insects of one family, the Gicindelidce, which have received the name of Tiger-Beetles, 
