Full discussion of the different classifications is unnecessary in this connection. Authors have differed in the past and will differ in the future as to what constitutes a natural system, and it would require many pages to give even a brief survey of the various schemes that have been proposed. As I have elsewhere said, “We must remember that classifications are but a means to an end—appliances to facilitate our thought and study—and that, to use Spencer's words, ‘we cannot, by any logical dichotomies, actually express relations which in nature graduate into each other insensibly.’”
The most philosophical, perhaps, of the more modern systems of classification is that of Friedrich Brauer, who has carefully studied the subject, and has given us an arrangement consisting of sixteen orders. This has many merits and has been adopted, with slight modifications, by Packard in his “Entomology for Beginners,” and by Hyatt and Arms in their recent and valuable text-book “Insecta.” Comstock, in his “Introduction to Entomology” strongly recommends Brauer's classification, but for reasons of simplicity and convenience adheres to a modification of the old classification of Westwood.
For purposes of comparison the classification by Hyatt and Arms, which is substantially that of Brauer, may be introduced.
In linear arrangement it is as follows:
| I. | Thysanura (Spring-tails, etc.). |
| II. | Ephemeroptera (Ephemeridæ; May-flies). (=Plecoptera Pack.) |
| III. | Odonata (Libellulidæ; Dragon-flies). |
| IV. | Plecoptera (Perlidæ; Stone-flies). |
| V. | Platyptera (Termites, Mallophaga, etc.). |
| VI. | Dermaptera (Forficulidæ; Earwigs). |
| VII. | Orthoptera (Locusts, Grasshoppers, etc.). |
| VIII. | Thysanoptera (Thripidæ; Fringe-wings). |
| IX. | Hemiptera (Bugs). |
| X. | Coleoptera (Beetles). |
| XI. | Neuroptera (Sialidæ, Hemerobiidæ; Lace-wings, etc.). |
| XII. | Mecoptera (Panorpidæ; Scorpion-flies). |
| XIII. | Trichoptera (Phryganeidæ; Caddis-flies). |
| XIV. | Lepidoptera (Butterflies and Moths). |
| XV. | Hymenoptera (Bees, Wasps, etc.). |
| XV. | Diptera (Two-winged flies). |
The relationship of these orders cannot be indicated in a linear arrangement, and is admirably shown by Hyatt and Arms by means of diagrams which I reproduce (Figs. 2, 3.)
Fig. 2.—Scheme illustrating origin and relationship of Orders. (After Hyatt.)
The relation of these sixteen orders to the older, septenary scheme is shown by the following arrangement: