INSECTS. 461 
during the whole period. When full grown it in most 
cases either descends into the ground, where it undergoes 
its transformations, first into a nymph, or pupa, and then 
into a beetle ; or it makes itself a rough coccoon of bits 
of stick and dead leaves, in which it changes into a pupa, 
and afterwards a beetle. The wood-eating beetles undergo 
their transformations in the tree on which they feed. The 
pupa of the beetle is what is termed incomplete; 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 always having at least eleven joints;) 
and a mouth, consisting of a labrum, or upper lip, alabium, 
or under lip, two mandibles, or upper jaws, and two max- 
illae, or under jaws. There is also the mentum, or chin, 
and a part called the clypeus, to which the upper jaw 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 membraneous wings, which are 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 spe- 
cies have been described ; of which about three thousand 
five hundred are natives of Britain. 
