The Parents' Review
A Monthly Magazine of Home-Training and Culture
"Education is an atmosphere, a discipline, a life."
Natural Science Recreations: Beetles
by Rev. A. Thornley, M.A., F.E.S.
It has been said that every man should have a hobby. I would rather say that every man should endeavour to add something to the stock of knowledge of his time. Many kinds of research, however, require much previous training before they can yield results of any value; and only he who had leisure and means can hope to achieve success in these quarters. A simpler task, and one requiring less special preparation, falls to the collector of natural objects, whatever they may be. A wide field, too, presents itself for choice; and if I endeavour in this paper to tell you something of the pleasure and instruction derived from collecting beetles, I do not wish you to infer that the collecting of these possesses any monopoly of advantage, or any superior pleasure over the collecting of other things which Nature supplies. Shells, plants, mosses, rocks, all exercise an exhilarating influence over the mind. The love of natural history ennobled the lives of such men as Robert Dick, botanist and geologist, of Thurso, and Thomas Edward, of Banff, as well as numerous others; and as an incentive to studies which this paper suggests, I would advise those, who have not already done so, to read the life of one of these patient searchers after Nature's truth. The study of Natural History possesses the great advantage also, of taking one out into the fresh air, thus tending to increase health, and supplying an antidote to the evils resulting from sedentary occupations or confining studies. Now, I labour under one great disadvantage in my present subject, namely, the prejudice which exists in the minds of some against beetles, nay, the very mention of the name produces in them a feeling of creepiness and horror. "What! collect beetles, cockroaches, and earwigs! ugh!" and, perhaps, some fair reader wrings her hands with dismay. She considers those ugly black beetles only fit to be trodden upon. Now, if I had time, I would set up a brief on behalf of these greatly maligned insects, which, I am sure, would lead you to respect them very much. However, at present, you must be content to learn that the cockroach and the earwig are not beetles. I admit, candidly, that both of our old friends just mentioned are very like beetles, and therefore, I must try to give you a good reason--only one out of many--why they are not put into the same class with the beetles. Suppose we had opportunities of watching the development of the eggs of the common earwig, and also those of some common beetle, say the cockchafer. Please don't confuse this with the cockroach. One morning we find that our earwig eggs have hatched; and what do we see? A number of little creatures very like the parent earwig from which they were derived. Just a few slight differences, and that is all. It is a very pretty, and not at all an uncommon sight, to see these little broods of baby-earwigs following their mother about, as chickens do a mother-hen. In a short time, also, our cockchafer eggs hatch, and we see resulting, a few little fat grubs, totally unlike their parent, and, indeed, possessing no resemblance to a beetle at all. In the natural state these grubs continue feeding at the roots of grass for over the space of a year, and after this assume another state, which is so remarkable and so typical of the whole tribe of beetles, that I will shortly describe it to you. The grubs, having finished feeding, become remarkably torpid. The body contracts, and slowly assumes a shape in which the lineaments of the perfect insect may be perceived. This is known and the pupa state. The word is Latin, and really means a "little doll." It is well applied, for the resemblance to such a puppet in swaddling-clothes is sometimes quite ludicrous. In this quiescent state the future cockchafer rests for a period of some months; but at last comes the mystic summons for it to awake from its long sleep; then, working its way through the soil to the surface, the pupa bursts, and out from it crawls the perfect cockchafer. A poor, soft, weak thing at first, but in a few hours its tissues harden, and then, when the sun is just setting in all the glory of the soft summer evening, it wings its way to the highest branches of some elm or oak, there to rejoice in the leafy wilderness for a season. This perfect form is called the imago, and in this state an insect never grows or alters at all. Many persons believe that little flies grow into big flies, and little beetles into big beetles. Here is a popular error. A little fly is always the same size, and so is a little beetle. All the growing was done in the grub stage. For this reason, size may form an important distinction between two species; whereas, if the perfect forms of insects increased in size, such a distinction would be useless. When next you see a little fly and a big fly on your window, you may be almost certain that they are distinct species. Now, these wonderful states through which so many insects pass are scientifically called a "metamorphosis." In the case of the beetle, you see how complete these stages are; but in the case of the earwig they are scarcely apparent at all. Herein, then, lies one great distinction between the order of insects to which our beetle belongs, and that to which the earwig belongs. We might put it in this way: an earwig is not a beetle, because it scarcely undergoes any metamorphosis. It is the same with the cockroach. So now we may dismiss them both, and return to our special study of beetles. Well, but we must have one for our study, and rather a large one. Where shall we get it from? Suppose you go out into the garden, and turn over a few fair-sized stones. There he is now! Just look at that ugly black fellow trying to make off as fast as he can. Don't be afraid; lay hold of him, and put him in a bottle. Take him in, and put him into quite boiling water. This is by far the readiest and best way to kill him, and not so cruel as stepping on them, and leaving them crushed, and only half dead, as some people do.
I would strongly recommend that children be forbidden to kill insects, and be warned at all times of the cruelty of tormenting flies and other insects. The method of killing suggested for scientific purposes is practically instantaneous, but the water must be quite boiling. For the sake of any "whose eyes grow tender over drowning flies," I suggest the following method: Take a wide-mouthed bottle, provided with a well-fitting cork. In this place a little cotton wool, then put into it the insects to be killed, and pour on to the cotton wool a few drops of ether, cork tightly up, and leave for half-an-hour or so. This will certainly kill all small beetles, and any large ones which escape its "hypnotic" influence, will be so still that they can be examined until they come round, and then let go. It should be remembered, however, that many beetles, particularly slow-crawling species, can be examined in the living state, when the machinery has the advantage of being seen in motion. If gently handled they take no harm. Bruised laurel leaf put into the collecting bottle kills most beetles, I believe, in a painless way; spirit of wine will do the same. We now proceed to examine our insect. If you have a small pocket-lens it will greatly help you.
It would take a very long time to understand the marvellous and complicated structure of a beetle, and I can only call your attention now to the simplest parts of its anatomy. It will be sufficient is at first, I ask you to notice that the insect consists of three well-defined portions; the head, the thorax, or chest, and the body. To the head are attached the antennae, or feelers. The form and structure of these organs is of sufficient importance to give the name and chief characteristic to some of the families, into which beetles are divided. Thus, in the Clavicornia (club-horned), the antennae end in a more or less distinct club. In the Rhynchophora, or Weevils, they are not only clubbed, but owing to the great length of the first joint, they are bent or elbowed: and this feature, together with the fact that the head is produced into a long rostrum, or beak, makes this family one of the easiest for beginners to recognise. Again, in the Lamellicornia, or Chafers, a very singular form of antennae is found. The club in this case is formed of from three to seven thin leaves or lamellae, a feature which can be well seen in the common Cockchafer. In the Longicornia (long-horned) the antennae are excessively long, sometimes longer than the body of the insect; and lastly, in some families, these organs are comb-like, saw-like, or perfectly simple. Now look at our specimen once more, and note the powerful mandibles or jaws; also some tiny organs, looking like very small, few-jointed antennae, these are the palpi. Finally, noticing the prominent eyes, we shall have seen all that is necessary, in such a superficial examination of the head. The second portion of our insect is the thorax, or chest. Its shape is very various, but the most important fact about it is, that all the six legs of the creature are attached to its under surface, and the wings, and wing covers, or elytra, to its upper. The third and last piece, is that which I have called the body, more strictly the abdomen: a large soft piece, consisting of a variable number of segments, and protected on its upper surface usually by the elytra, though in many beetles these are so short as to leave many segments of the abdomen exposed, and in this case, the upper surface is more or less of a horny texture. In the Staphylinidae, a family to which that fierce looking monster "the Devil's Coach Horse" belongs, the elytra are exceedingly short, and many persons would never suspect that these creatures were beetles at all. Attached to the thorax are six legs: each leg consisting of three well-marked portions. A femur, or thigh, a tibia, or shank, and a tarsus, or foot. This latter consisting usually of from three to five small joints. The whole leg is articulated with the under side of the thorax, by a small joint, generally sunk in the latter and called the coxa. Very frequently may be observed a small piece articulated between the coxa and the femur; this is the trochanter. But it is to the elytra, or wing covers, present in all beetles that the order owes its name of "Coleoptera," or sheath-winged insects, and it is to some peculiarities of the elytra that I must now very briefly call your attention. Take your specimen in hand, and then with a pin gently separate the wing cases. In most beetles this is easily accomplished, and oftener than not, a beautiful pair of ordinary membranous wings will be observed folded up beneath them. In a few beetles, the elytra are soldered together, and then of course, the pair of membranous wings is wanting. The elytra may be perfectly smooth, or covered with hairs, or beautiful lustrous scales. But more frequently they are marked with fine longitudinal grooves, called striae; and these latter are frequently punctured; that is, present an appearance as if they had been pricked with a needle, not quite through. It is very marvellous the infinite variety of pattern produced by this devise of lines and punctures. It renders the separation of species, otherwise very similar, quite an easy task. But space will not allow of my lingering any longer over these anatomical detains, for I must conclude this paper with a very brief account of the modes of capturing and preserving beetles.
Now the latest catalogue of Coleoptera informs us, that there are 3243 species of beetle inhabiting Great Britain and Ireland. Many of these are very small, and some are very rare. But this rarity is often due to the want of collectors. The so-called "good localities" frequently being so from the fact that, through the presence of an energetic collector, the district has been systematically worked. Come with me on an imaginary expedition. We will suppose it is that bewitching time of the year when the hawthorn is in full blossom. We take in our pockets several strong wide-mouthed bottles of different sizes, provided with well-fitting corks, through which we have passed a piece of glass tubing, or a quill, plugged with a little cork. It is a very simple matter to pass an insect down the tube into the bottle, and much better than having to remove an ordinary cork to which the insects frequently cling, and may be lost at each removal. Inside our bottles we place a few crushed laurel leaves, or at least a little moss, or even paper, simply to afford a foothold for the little creatures and prevent them from damaging one another by too great crowding together. A few tin boxes, a large white calico net, for sweeping grass, flowers, or low herbage; an old umbrella, into which we can beat tress and shrubs; and, if we are likely to visit any ponds on the way, a small fishing-net of muslin, and we shall be ready for any amount of beetles. Now we reach our hawthorn blossom, and begin gently to beat the branches into the open umbrella. What a shower of insects! Small beetles, spiders, caterpillars, and bugs, and perhaps amongst them a beautiful longicorn or chafer. By way of change, we now apply the sweeping-net to the long herbage at the roadside, and we are again rewarded by a motley collection of small and great, soldiers and sailors, little blue apions and other small weevils, tiny jumping beetles of the family Phytophaga, and numerous strange insect forms. But the stones! we must not forget them. Gently turning over all the decent-sized ones, we obtain a variety of active ground-beetles (Geodephaga) and cock-tails (Staphylinidae). These must be put into a bottle by themselves, as they have no compunction in eating up all smaller cousins. The laurel leaves in the bottle should, however, keep them quiet for some time.
And so we go on; filling our bottles and tins. Nearly all the year is good for beetle collecting--spring and autumn, I think, are the two best seasons. In winter, moss from sheltered localities may be collected in bags, and shaken out over white paper at home, when a great number of small Coleoptera may be obtained. In autumn, it is worth while to examine fungi, particularly those which are just beginning to rot. Numbers of fine cocktails and Clavicornia may be thus got. When home is reached, these beetles which are not already dead must be killed, as intimated above, and carefully dried on blotting-paper. The larger species should then be pinned (with a proper entomological pin, if possible) through the right wing case. The smaller species are mounted on nice, fine, thick cardboard with gum tragacanth. It is best to make this several weeks before using, as it improves greatly with a little keeping. Add a few drops of vinegar to it to prevent the formation of mould. Now place your little beetle on its back, hold it with a pair of forceps whilst you brush out, with a camel-hair pencil, its legs and antennae. Then transfer it, right way up, to a card on which you have placed a drop of your gum. Next, with a needle, fitted into a wooden or cork handle, stretch out its antennae, and set out its legs, so as to make it present just as natural an appearance as if it were walking. If the beetle is very small, this work will have to be done under a lens of low power, a task which practice will soon perfect. When dry, the specimens can be cut off, a small pin put through the card, and the insect placed in a corked box or cabinet. Very small beetles may be mounted several together on one piece of card. Each specimen should be numbered and a record kept in a journal of the time, place, and circumstances of its capture. My space is now all used up, and I will merely add, that I will gladly supply more detailed information to any readers of this article who may desire it. Further, I would gladly name any specimens they choose to send to me.
|Top||Copyright © 2002-2014 AmblesideOnline. All rights reserved. Use of these resources subject to the terms of our License Agreement.||Home|