434 THE INSECT WORLD. 
in flying; they are sheaths more or less hard, sometimes varied 
with bright colours, and never crossing over each other. The pos- 
terior wings are membranous, presenting a ramification of veins, 
and usually folding up under the elytra, which protect them when 
at rest. The mouth of Coleoptera is provided with mandibles, with 
jaws, and two quite distinct lips, and is suited for mastication. They 
undergo complete metamorphosis. After an existence of greater 
or less extent in the larva state (in the case of the cockchafer 
three years), the insect changes into a pupa, which remains in a 
state of complete immobility. After a certain time, the pupa 
bursts its envelope and assumes the form of a perfect insect. 
The Coleoptera present the utmost variety of habits as regards 
their habitations and food. One does not find in this Order 
those admirable instincts, those manifestations of intelligence, 
which bring certain Hymenoptera near to those beings which 
are highest in the animal scale; but they offer peculiarities very 
well deserving serious and profound study. Some are carnivo- 
rous, and thus they are useful to man in destroying other noxious 
insects, which they seek on the ground, on low plants, on trees, 
and even in the depths of the waters. Many of these Coleoptera 
feed on animal matter in a state of putrefaction. We may look 
on them as useful auxiliaries: they are Nature’s undertakers. 
A great number live in the excrements of animals. The 
dung of oxen, buffaloes, and camels afford shelter to Coleoptera 
of different families, which thus live on vegetable matter more 
or less animalised. Others attack skins and dried animals in 
general; and some are the pest of entomological collections. Lastly, 
immense legions of Coleoptera are phytophagous; that is to 
say, they attack roots, bark, wood, leaves, and fruits, and cause 
much annoyance to the agriculturist. Above all, the larve are to 
be dreaded. Those which live in wood may in a few years 
oceasion the loss of trees, vigorous and full of life ; or completely 
destroy the beams of a building. Certain larvee, such as those of 
the cockchafer, eat away the roots of vegetables, and so destroy 
the harvests. Others, lastly, devour the leaves and the stalks of 
plants, attack the flowers in the gardens, or the corn in the barns ; 
and so man makes desperate war against them. 
In the immense variety of known Coleoptera we must be con- 
