Australian insects

CLASSIFICATION.

In considering the classification of our insects, I have on the whole followed that adopted by Sharp in his “Insects” (vol. v., vi., 1895, 1899), Cambridge Natural History, but at the same time have considered it advisable, in a work of this kind, to leave out whenever possible the definition of the smaller sub-divisions. I have also made one important alteration in his scheme of classification by placing the Termitidae after the Blattidae, following on with the Embiidae and Psocidae, as I consider that these are nearer primitive Orthoptera than Neuroptera in their wing structure; we thus do away with Pseudo-Neuroptera that has always appeared to be an unnecessary division; and we should have the courage of our convictions and place them on one side or the other.

In zoological classification, the sub-kingdom Arthopoda, comprising creatures whose bodies are composed of rings or segments, and jointed legs, contains four large groups: (1) Arachnidae, spiders, mites, ticks, and scorpions; (2) Crustacea, crabs, shrimps, wood lice, &c.; (3) Myriapoda, centipedes, millepedes, &c.; (4) Insecta, insects; and a fifth group, Onychophora, containing the Peripatus, is now included. Though these creatures are broadly related, insects are readily distinguished from the members of the preceding groups.

The word Entomology is derived from two Greek words, Entomos, an insect; and Logos, a discourse. Insects are arranged by entomologists in Orders, Families, Genera, and Species. The first clearly-defined classification was published by Linnaeus in his “Systema Naturae,” 1758, where he divided them up into seven great orders; namely, Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Hymenoptera, Diptera, and Aptera, distinguished by the number and structure of the wings. Later on (1778) Fabricius founded another classification, based on the structure of the organs of the mouth, but this artificial arrangement soon became obsolete.

In 1815, Kirby and Spence issued the work in four volumes entitled “An Introduction to Entomology or Elements of the Natural History of Insects,” a second revised edition coming out in 1816. This was the first attempt in England to popularise entomology, and to give the ordinary reader an idea of classification. In it will be found a great deal of general information that all young entomologists should read.

In Westwood’s “Introduction to the Modern Classification of Insects,” published in 1839, a great advance was made, and the science placed on a sound footing; this has been a great help to all workers. He divided the insects into thirteen orders; but, though the tendency of American and European writers has been to increase these divisions, we have reduced them, and in Kirby’s “Text Book of Entomology” only seven are used. In the last work, “Insects” (Cambridge Natural History, 1895), by Sharp, the same seven orders are used, though in a somewhat different manner, with the addition of an eighth, Thysanoptera, to contain the single family Thripidae.

The correct naming of insects is based on the following rules: First comes the Order, which may contain a number of Families, all with certain peculiarities; as, for example, the straight-winged insects, Order Orthoptera, of which we will take the Family Acridiidae, “locusts.” This Family is again subdivided into smaller divisions or groups, called Genera; all the individuals comprised in the Genus have some well-defined external characters that form a common link binding them together: the individuals are known as Species. Therefore each insect when it has been described has a generic or group name, and a specific or individual name. The generic name should be based on some Greek or Latin root, preferably the former, but it cannot of course be compounded from both languages; it should on translation give some clue to the general distinctive character of the group. The specific name should be derived from Latin, and give the student some idea of the locality, markings, colour, or shape of some part of the insect under observation; thus, Locusta australis, Brunner, is the southern locust or grasshopper. As a matter of convenience to students, the name or abbreviated name of the entomologist who first described the insect follows the name when mentioned in scientific articles or catalogues, but is not usually done in general work.

The rules here laid down, however, are much more observed in the breach than in the observance. In former times most descriptions of insects were written in Latin, but at the present time they are being described not only in English, French, and German, but many other languages difficult for the ordinary English student to translate, such as Russian, Bohemian, Hungarian, &c., so that it is very difficult in many instances to find out whether some generic names have any meaning. The difficulty of creating generic names with pure roots that are not preoccupied by previous writers is always increasing, and to save the trouble of going through the lists of genera already in use, many zoologists use the names of other naturalists, names of localities, or “nonsense” names compounded of a jumble of letters. Then, again, when the genus is an extensive one containing many species, the describer gives it the Latinised name of the collector or some friend he wishes to honour, so that we may come across both a generic and specific name that throws no light on the identity of the insect. As an example, Grabhamia curriei; Coquillett named this mosquito in the first instance Culex curriei, Currie’s mosquito, which was consistent, but Theobald found on subsequent examination that it belonged to his Genus Grabhamia, dedicated to Dr. Grabham.

Even without these drawbacks, a beginner naturally finds the classification of insects a serious task, and the simple committing to memory of the scientific names a big undertaking; but when he has once grasped the rudiments, the system will soon appear to him.

One of the most difficult things the popular writer meets with in scientific work is to find a suitable vernacular name to fit a common insect; a beetle may be bright yellow, with a brown head; the first man comes along and calls it the “Yellow-bodied Beetle,” another passes by and says it is the “Brown-headed Beetle,” yet neither would be quite accurate or define its main peculiarities. Again, we often find a popular name that designates a particular insect in one district is used for quite a different species in another part of the State: quite recently I asked several correspondents for specimens of the beetle in the Maitland district known as the “Jackeroi,” and had four distinct species of weevils forwarded under that name. The “Dicky Rice” is the name given to a tiny grey weevil (Prosayleus phytolymus) by the orchardists about Windsor, but in other districts it is used indiscriminately for a number of other weevils.

Should any one take up a box full of unnamed and unclassified insects, he will feel like a stranger in a picture gallery without a catalogue; for, while everything is very beautiful, how much more interesting if he only knew something about the subject; for the same reason, each insect named and arranged has an individuality that it did not previously possess.