In looking at an insect, we perceive that it is naturally divisible into three principal parts: first, there is the head, or _caput_; next, the trunk, or _thorax_; and thirdly, the hinder portion of the body, or _abdomen_. If we turn to a Latin dictionary, and hunt out the word _insecta_, which is the Latin term for "insect," we shall find that it is derived from a verb which signifies "to be cut in," or "notched." From this we see that the very word _insect_ has arisen from perceiving what we are now alluding to, the natural notching of the body of these creatures into certain portions. We mentioned, however, at page 89, that the insect in the _larva_ form had a body which was, in almost every instance, divided into _thirteen_ segments, or parts. It may be asked, Are these all lost in the perfect insect; or are they still to be traced in it? They are still to be traced in it. The head is one, three form the trunk or thorax, and the remaining number constitute the abdomen: but, in order to save disappointment, it must be added, that it is rare to find the full number of segments or distinct parts in the abdomen; we seldom, in fact, find more than seven or eight, the remaining two or one being generally hidden. It is interesting, however, to trace in the perfect insect these indications of its previous larval condition, especially when we remember the strange appearance it underwent while a pupa.
Now the various parts in the _head_ division are, to speak generally, the _head proper_, the _mouth_, the _eyes_, and the _antennæ_. Entomologists describe a large number of other parts, which would also be mentioned here if this little treatise were intended to give a minute account of the insect's anatomy; and those features which are of most prominence and importance, will be mentioned in addition when we come to speak particularly of these several chief organs.
The middle portion of the insect, or _thorax_, is divided into three parts--a front, middle, and hinder part; or, in the language of entomology, a _pro-thorax_, a _meso-thorax_, and a _meta-thorax_. Attached to the thorax are the _wings_ and the _legs_. The remaining portion, or _abdomen_, is furnished with organs and appendages, not requiring special mention in this place.