OF INSECTS. 
181 
contrivances in the bodies of insects, neither dubious in 
their use, nor obscure in their structure, and most properly 
mechanical. These form parts of our argument. 
I. The elytra, or scaly wings of the genus of scarabaeus 
or beetle, furnish an example of this kind. The true wing 
of the animal is a light transparent membrane, finer than 
the finest gauze, and not unlike it. It is also, when ex¬ 
panded, in proportion to the size of the animal, very large. 
In order to protect this delicate structure, and perhaps 
also to preserve it in a due state of suppleness and humidi¬ 
ty, a strong hard case is given to it, in the shape of the 
horny wing which we call the elytron. When the animal 
is at rest, the gauze wings lie folded up under this impene¬ 
trable shield. When the beetle prepares for flying, he 
raises the integument, and spreads out his thin membrane 
to the air. And it cannot be observed without admiration, 
what a tissue of cordage, i. e. of muscular tendons, must 
run in various and complicated, but determinate directions, 
along this fine surface, in order to enable the animal, either 
to gather it up into a certain precise form, whenever it 
desires to place its wings under the shelter which na¬ 
ture hath given to them; or to expand again their folds, 
\tfhen wanted for action. [PI. XXXII. fig. 1.] 
In some insects, the elytra cover the whole body; in oth 
ers, half; in others, only a small part of it; but in all, they 
completely hide and cover the true wings. [PI. XXXII 
4g. 2.] 
Also, many or most of the beetle species lodge in holes in 
the earth, environed by hard rough substances, and have 
frequently to squeeze their way through narrow passages; 
in which situation, wings so tender, and so large, could 
scarcely have escaped injury, without both a firm covering 
to defend them, and the capacity of collecting themselves 
up under its protection. 
II. Another contrivance, equally mechanical and equal¬ 
ly clear, is the aivl or borer, fixed at the tails of various 
species of flies; and with which they pierce, in some 
cases, plants; in others, wood; in others, the skin and 
flesh of animals; in others, the coat of the chrysalis of in¬ 
sects of a different species from their own; and in others, 
even lime, mortar, and stone. I need not add, that hav¬ 
ing pierced the substance, they deposit their eggs in the 
h ole. The descriptions which naturalists give of this organ, 
are such as the following: it is a sharp-pointed instru¬ 
ment, which, in its inactive state, lies concealed in the 
extremity of the abdomen, and which the animal draws 
Q 
