Coleoptera, or Beetles. 553 
imago. There are, however, some insects which are 
active throughout their lives, and in these the larvae and 
pupae are very similar to the perfect insect. The perfect 
insect is divided into three segments, or parts, called the 
head, the thorax, and the abdomen. 
Order I. Coleoptera, or Beetles. 
The larva of the beetle is a grub, which often continues 
in that state three or four years, eating voraciously 
during the whole period. When full grown it in most 
cases either descends into the ground, where it under- 
goes its transformations, first into a nymph, or pupa, and 
then into a beetle ; or it makes itself a rough cocoon of 
bits of stick and dead leaves, in which it changes into a 
pupa, and afterwards into a beetle. The wood-eating 
beetles undergo their transformations in the tree on 
which they feed. The pupa of the beetle is termed in- 
complete, because all the parts of the insect are visible 
in it, instead of being enclosed in one thick covering, as 
in the moths and butterflies. The head of the beetle 
is furnished with two compound eyes; two antennae 
(differing in shape in the various species, but having 
usually eleven joints); and a mouth, consisting of a 
labrum, or upper lip, a labium, or under lip, two man- 
dibles, or upper jaws, and two maxillae, or under jaws. 
There is also the mentum, or chin, and a part called the 
clypeus, to which the upper lip is attached. 
The thorax is the part which supports the legs and 
wings. The legs are divided into five portions, of which 
the part terminated by the claw is called the tarsus. 
There are two membranous wings, covered by two 
hardened wings or wing-cases, called the elytra, which 
generally open by a straight line down the back ; and 
hence the name of Coleoptera, which signifies wing in 
a case : the abdomen is simply the body. 
The number of beetles is very great, and indeed Mr. 
Westwood informs us that more than thirty thousand 
species have been described, of which about three thou- 
sand five hundred are natives of Britain. 
