1621. On the arrangement or classification of insects. Having gained a general knowledge of those forms and appearances which insects assume before they reach their perfect state, the student should next make himself acquainted with their classification, and finally with the nomenclature of such as are most interesting. The first may be acquired by an attentive perusal of the following characters; but to ascertain the name of a species, or to know whether any particular insect has been described, recourse must be had to books or to those persons who have made entomology their particular study.