« AnteriorContinuar »
ART. I.-— The Library of Entertaining Knowledge.- Insect Miscellanies.
12mo. pp. 414. London : Knight. 1831. It was obvious that Mr. Rennie's former volumes, those upon Insect Architecture, and Insect Transformations, could not well have comprised all the matter which, in the course of his inquiries, he must have accumulated upon his hands. He reserved, therefore, for a miscellaneous volume, many interesting chapters, which in either of those works would have been altogether out of place, and has thus contrived to make the history of those wonderful objects of creation as popular and amusing as possible. He may well endure the cold and contemptuous sneer, with which his labours have been received by those, who hold that science can never be communicated unless in a pedantic form, and that it was never intended for the use of the people. We believe that his productions, printed under the superintendance of the Society for the Diffusion of Knowledge, have done a great deal of good, and have induced many persons to give their attention to natural history, who, but for these cheap and widely-circulated books, would never have bestowed a thought upon it.
We have read with particular pleasure the Chapter (XIV.) in the present volume, on the collection and preservation of insects for the purposes of study, which abounds in the most useful suggestions. The author here clearly and admirably lays down a principle for the guidance of our inquiries, which ought never to be lost sight of, namely, that an insect can never be found in any situation, nor make any movement, without some motive, originating in the instinct imparted to it by Providence.' Such a principle as this is not only founded in truth, but capable of conferring a great moral interest upon every step we take in the course of our investigations. Even if he be not acquainted with any systems of classification, it will not be difficult for any intelligent person to become a good naturalist, merely by dint of actual observation.
VOL. III. (1831.) NO. IU.
Insects of many kinds are constantly crossing his path, whether he remains at home, or ranges through the woods and fields. Let him fix for a while, as the author recommends, upon one of these,
mark its progress from the egg till its death, its peculiar food, the enemies which prey on it, and the various accidents or diseases to which it is liable, and he will possibly be able to communicate interesting and valuable additions to the history of animated nature.
An illiterate labourer, at Blackheath, has done this to a considerable extent, and any person may do it without knowing the name even of a single insect. He may number them, or class them in alphabetical order; he will find them wherever leaves or flowers grow, in running and stagnant waters, on the earth and in the air, in countless multitudes. The best apparatus for keeping them is a common tumbler glass filled with the materials, from amongst which the insect has been taken.
Its operations may thus be easily inspected from day to day. The top of the glass may be covered with gauze, or it may be inverted, taking care to secure the admission of air round the edge by inserting slips of card at intervals. Small paste-board boxes may be used for the same purpose. With this simple machinery, and the knowledge of a few leading rules, which Mr. Rennie has clearly and judiciously laid down, every man may become a naturalist to an extent quite sufficient to afford him delightful occupation for his leisure hours, and especially to bring him, as it were, constantly into the presence of the Deity, by inducing him to contemplate the varieties of insect existence, that perpetually court his observation.
For instance, will it not open to him a new and most interesting view of the provisions of creative wisdom, if he can discover that the wings of insects are furnished with nerves, by means of which they are capable of directing their flight, without receiving any assistance from their eyes? We do not consider this as a fact proved merely by the curved or circular course, which bees are generally supposed to take in returning to, and departing from their hives; for, according to our present information, we might with equal probability assume, that such a course may be suggested to them by that natural instinct, which teaches them to conceal their treasures from the depredation of their enemies, as much as they
The carrier pigeons are also said to prefer a similar mode of flight, both in departing from an unknown station, and in arriving at their home from a distance. Perhaps the true cause of this may be, that they experience less resistance from the atmosphere in adopting that course, than if they were to pursue a straight line, But the facts mentioned with respect to Spallanzani’s bats are calculated, it must be owned, rather to favour the supposition that, so far as bats are concerned at least, there is a delicacy of touch in their wings, which serves them instead of eyes. From several cruel experiments which he made, he found that..bats, when blind-folded, and even when their eyes are destroyed altogether, and leather glued over the sockets, can fly nearly as well as before,
and can avoid in their flight the smallest threads and other objects hung up to interrupt them. They can even dart through a hole in a net or curtain, large enough to admit their passage, and that without previous examination. They can likewise thread the mazes of a cavern, without hurting themselves on the walls, and go directly to their nest holes. When Spallanzani destroyed the ears and nostrils, as well as the eyes of bats, he found that they could direct their flight equally well.' Cuvier has explained these facts, by shewing that the wing of the bat is analogous to the hand, being one continued tissue of exquisitely sensible nerves, covered with a fine skin, which is furrowed like that on the human fingers. Such an instrument of locomotion as this is peculiarly useful to the bat, whose excursions in search of moths are uniformly made in the twilight or the night, and thus our inquirer will see throughout, the care of a Providence always adapting the means to the required
It seems to be pretty well ascertained, that many insects are delicately sensible to changes of temperature. Previously to bad weather, ants are always seen very careful in securing their eggs from its effects, and let the day be ever so apparently fine, they will not place their eggs at the top of the nest, if there be the least chillness in the air. Increased heat, arising from the agitation of bees in a hive, is said by Huber to be the cause of those emigrations from the parent hive, which periodically take place. He adds, that, even upon ordinary occasions, they are so much afraid of bad weather, that a single cloud passing over the sun will make them suspend their labours, and retreat homewards. It was observed by D’Isjonval, that spiders had a good knowledge of weather, that when it was wet and windy they spun only very short lines; but that “when a spider spins a long thread, there is a certainty of fine weather for at least ten or twelve days afterwards.” Kirby considers this statement in the main accurate, and thinks that a very good idea of the weather may be formed from attending to these insects. Mr. Rennie concludes from his own observations, that this theory can only be supported as far as the winds are concerned at the time the framework, that is to say, the collection of stayropes, of the web is constructed, but no farther. Our acquaintance with the operations of this most interesting and ingenious of all insects, rather induce us to incline to the opinion of Kirby, the more particularly, as Mr. Rennie's dissent from it is founded upon the theory, that the spider's lines are floated in the air, and that it is by mere accident that they catch the object to which the insect intends that they shall be attached, in order to secure the support of the future web. We are convinced that this theory is altogether erroneous, and that the spider itself attaches both the extremities of the line to the objects to which it is found adhering. By what process this object is accomplished, is a question upon which natural philosophers have put fortlı different opinions. Our own
observations, for we have frequently watched the proceedings of these creatures, would lead us to believe that, having fastened one end of the thread to a branch of a tree, or any other object, they let themselves down to the ground by means of that thread, and then direct their steps to the object to which they wish to fasten the other extremity. They then pull the rope as tight as they may find necessary, in some cases allowing for a curve in the line, such as we see in chain bridges, and gathering up all the useless portion of the line, they leave it upon an adjacent leaf or twig. They then return by the line thus fastened to the spot whence they set out, and so form the whole of the outworks of the web. We have seen threads of this kind, of four or five yards and more in length, in very fine weather, connecting the back wall of a house with a shrub at some distance from it, under circumstances which shewed that it was impossible for the floating doctrine to apply.
We can add our testimony to the statement made by Mr. Rennie, that the spiders are seldom seen making or mending a web during bright sunshine. They are generally found most busy at that work during cloudy weather, the reason, probably, being that it is then, while the scorching rays of the sun are absent, the geometrical lines of the web can best be glued to each other. It is well known that spiders hunt with most success at night, the unfortunate flies then in motion not being able to discover so easily the toils which are prepared for their destruction. It is remarkable that some insects appear only during particular hours of the day; for instance, the clouded yellow butterfly does not fly before ten, and retires to rest soon after four o'clock. The red underwing moth is only to be seen about six or seven o'clock in the morning, and never at any other time. Some of the smaller beetles swarm only before noon, when they disappear; generally also, unless the evening be more than usually bright and warm, the gnats after dancing their quadrilles an hour or two, vanish at sunset. The history of plants furnishes several facts analogous to these. It is conjectured that insects are peculiarly sensible to electric changes in the atmosphere, but it is admitted that there is not evidence to reduce this conjecture to any thing like a certainty.
We believe that nobody who has even paid any attention to the habits of insects, can doubt that they possess in a high degree the sense of taste, although that sense is in many cases governed by rules with which we are not acquainted. Mr. Rennie, in proof of this, mentions a fact that came within his own notice in Scotland,
where the midge, a very small kind of gnat, was so very troublesome to a party of haymakers, that it was with difficulty they could continue their work; yet, notwithstanding the general attack made by the insects, wherever they could find a spot of uncovered skin, one individual among the haymakers was never touched, while the skin of his companions was covered with bites as if scourged with nettles. In the same manner of two individuals, who had been
together for a whole day nutting, and who slept in the same bedchamber, one was found next morning covered all over with red blotches, from the attacks of the harvest bug, while the other was quite untouched. It is within the experience of every body who has had the misfortune of sleeping in a bed infested by fleas and bugs, that both these abominable insects evince a decided preference for women and children, and that when they can satiate themselves upon these victims, they seldom attack the stronger sex.
Naturalists have discovered in more than one species of insect vessels which supply them with saliva; and it is a curious fact, ascertained by observation, that when a fly is about to devour sugar left in its way, it first emits upon the sugar a small drop of fluid, in order to melt it, and thereby render it easy to be sucked up.
There can be no doubt that insects very generally are endowed with the sense of smelling. What is most curious in this part of their history, is the probability that many of them have the means of employing offensive odours, which nature has enabled them to discharge, in order to avert the pursuit of their enemies. Thus the small green beetle, which is not uncommon near London, defends itself by a kind of artillery, from which it discharges both noise and smoke. There is another species called the bombardier, known by its head and thorax being brick red, and the rest of the body of a blackish hue. When we attempt,' says Mr. Rennie, quoting Rolander, “lo catch it, we are surprised by a discharge resembling a pop-gun, accompanied with a sort of smoke, of which it is furnished with a bladder sufficient to fire off twenty shots in succession. If this chance to get into the eyes, it will make them smart as if they had been bathed with brandy. Its chief enemy is a beetle larger than itself, which hunts it without mercy. As it finds it impossible to escape by speed of foot, it stops short, and awaits its pursuer; but just as he is about to seize it, he is saluted with a discharge, and while he is for a moment stupified with surprise, the bombardier endeavours to gain a hiding place.'
Shakspeare, to whom the whole volume of nature seems to have been opened, was aware that insects had also the faculty of hearing. Mamilius in the Winter's Tale, says:
“ I will tell it softly,
You crickets shall not hear it." The information collected by Mr. Rennie upon this subject, is amusing as well as curious :
It is well known to every boy that the field one, of a fine green colour, which during the summer months is by no means sparing of its stridulous music, instantly ceases to crink the moment it hears a foot fall; and hence it is not easy to discover the spot where it is, unless it be approached in the most cautious manner, for it is silent if a person approach within several yards of it. Brunelli, an Italian naturalist, tried some experiments upon