If the reader has made no progress in the study of natural history, he will probably find it difficult to understand the several _names_, or _terms_, the different parts of insects are called by; and which occur in every description. For this reason I think it incumbent on me to give the most plain and familiar explanation of them I possibly can. This I have done two ways; by methodical definitions, and figures; and in both of them shall make no scruple to follow the method laid down by that great master of natural history, the judicious Linnæus, whose excellent plan, for the knowledge and classing of insects, demands the utmost thanks and regard from every lover of this branch of science. From his plan I have taken the hint of giving some figures of different genera, with the proper names of the respective parts in a plate by themselves. By these the reader will not only be greatly assisted in understanding the descriptions; but it will enable him to class them with more facility, if he is inclined to do so. I therefore go on to explain, first the _terms_ used throughout the whole; and afterwards the distinct and different _parts_ of insects. In doing this, I divide them into ORDER, CLASS, GENUS, and SPECIES. _Order_, is a general term, applicable to a whole race of animals, whereby they are distinguished from each other, as beasts, birds, fishes, &c.[13] _Class_, a term by which insects, as well as other animals, are divided into their respective genera or tribes, as the farinaceous, crustaceous, transparent, &c.[14] _Genus_, a term dividing each class, as butterfly, moth, hawk-moth, constitute the farinaceous (Lepidoptera); dung-beetle, lady-bird, goat-chaffer, and many others, make up the crustaceous (Coleoptera); cockroach, locust, bug, and some others, form the semi-crustaceous (Hemiptera, Linn.), &c.[15] _Species_, a term comprehending a distinct or individual sort in each genus, as the pearl-bordered, admirable, skipper, &c. among the butterflies; egger, drinker, peppered, &c. among moths, &c. To these I must add the word _Variety_, a term by which two insects of the same species are known, though differing a little (not characteristically) in colour, size, &c.[16] {xxiii}I shall next proceed to explain and describe the different parts composing insects, by dividing them into the Head, Thorax, Abdomen, and Limbs.[17] The HEAD (Fig. 1, 2, 3, _a_.) includes the ANTENNÆ, MOUTH, PALPI, EYES, TONGUE, JAWS, and HORNS. The _Antennæ_ are formed of various shapes, according to the different genera, as may be observed in the figures, and seem instituted by nature not only for guiding the animal in its passage, but likewise for other purposes; being endued with an exquisite sense of feeling and perception. Fig. 1. _d d_. Fig. 2. _c_. Fig. 3. _c c_.