COLEOPTEROUS INSECTS. 
75 
functions which they perform in the economy of 
nature, and the injurious consequences which not 
unfrequently result to mankind from their undue di- 
minution or increase, impart a greater degree of im- 
portance to their history than attaches to the gene- 
rality of the insect tribes. 
Coleopterous insects compose the first great sec- 
tion, or order as it is called, of the class of insects. 
They are readily distinguished from the other mem- 
bers of their class, by having the inferior wings co- 
vered and protected by a hard case or shell. This 
peculiarity of structure has suggested the name, 
which is composed of two Greek words, and signi- 
fies wings in a sheath (xoXao;, a sheath , and ftrija, 
wings). The term was first used by Aristotle, and 
as the character to which it refers forms a very ob- 
vious mark of distinction, it has been almost univer- 
sally adopted by subsequent writers. In several in- 
stances, however, it fails to be an accurate defini- 
tion of the order, for there are some beetles without 
either wings or sheath, and many others in which 
the latter only is present. To the other characters 
more recently added, such as the transverse folding 
of the wings, and the straight- sutural line down the 
middle of the wing-cases, separating them into two 
equal portions, there are likewise exceptions ; but 
these are too few and unimportant to invalidate ma- 
terially the general correctness of the definition. 
The insects to which these characters apply, con- 
stitute one of the most numerous orders of their 
