Again,

some insects have antennae in front of their eyes, as the
butterfly and the horned beetle. Such of them as have the power of
jumping have the hinder legs the longer; and these long hind-legs
whereby they jump bend backwards like the hind-legs of quadrupeds. All
insects have the belly different from the back; as, in fact, is the
case with all animals. The flesh of an insect's body is neither
shell-like nor is it like the internal substance of shell-covered
animals, nor is it like flesh in the ordinary sense of the term; but
it is a something intermediate in quality. Wherefore they have nor
spine, nor bone, nor sepia-bone, nor enveloping shell; but their
body by its hardness is its own protection and requires no
extraneous support. However, insects have a skin; but the skin is
exceedingly thin. These and such-like are the external organs of
insects.

Internally, next after the mouth, comes a gut, in the majority
of cases straight and simple down to the outlet of the residuum: but
in a few cases the gut is coiled. No insect is provided with any
viscera, or is supplied with fat; and these statements apply to all
animals devoid of blood. Some have a stomach also, and attached to
this the rest of the gut, either simple or convoluted as in the case
of the acris or grasshopper.