EGG RAFTS OF THE GNAT. Page 12.
THE
LIFE OF AN INSECT;
BEING
A HISTORY OF THE CHANGES OF INSECTS FROM THE
EGG TO THE PERFECT BEING.
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APPOINTED BY THE SOCIETY FOR PROMOTING
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PART I.—THE EGG.
PAGE
Chapter I.—The Nest.—The Microscope and Telescope—Terror caused by Insects—Death-watch—Life-boat of Eggs—The Water Beetle—Floating Ark of Eggs—The Gnat—her difficulties—her Egg-raft—The Sand-boring Wasp—Towers of rubbish—Captive Caterpillars—Wood-boring Bee—An Insect Nursery—Escape of the young—Tapestry Bee—A Nest lined with Poppy-flower Petals—Enchanted Leaf-tubes—The spell broken—The Insect Sorcerer—Nest of Down made by a Moth—The Lackey Moth—The Ichneumons—Their usefulness
Chapter II.—Structure and contents of the Egg.—Its Shape—Remarkable mistake about an Insect—The Lace-wing Fly—Eggs carved on their surface—Colours of Eggs—Changes of Colour—Eggs of the Garden Spider—Pretty Nests—Anatomy of the Egg—Contents of the Egg
Chapter III.—Life begins in the Egg.—Spring Time—Influence of Heat and Cold—Eggs resist great Cold—The time of Hatching—Escape of the new Creature—Connexion between Plants and Insects—Changes in the Egg—A Spider's Mother's love—Experiment with two Spiders—Anecdote of an Earwig—Enormous number of Eggs of different Insects
PART II.—THE LARVA.
Chapter I.—The Young Larva.—Affection of a Field-Bug—An Earwig Mother—Anecdote of a Spider—Ant-Nurses—Varieties of Larvæ—The Larva born—Forms of Larvæ—Larvæ of Butterflies—Structure of a Larva
Chapter II.—Habits of the Larva.—The Lion of the Aphides—its Courage—The Ant-Lion—The "Giant Grim" of Insects—Formation of its Trap—An Insect Excavator—The Den—A Stone in it—A captive Ant—Principle of Compensation—The Sand-Wasp's Den—A Warrior-Wasp—An Insect Duel—The Kakerlac and the Bandit Wasp—The Corpse carried home—A Wasp clad in the Wings and Limbs of Insects—The Tiger Beetle Larva—Dragon-Fly Larva—its curious Mask—a ferocious creature—Ravages of Cockchafer Larvæ—Lamp Oil got from Larvæ—"Old Father Long-legs"—The Gamma Moth and its Larva—Magical Origin of—The excessive numbers of the Larvæ—Destruction of Trees by Larvæ—Killed by rain—The Weevil—Insects on board Ship—Appetite of Larvæ—Silk-Worm Larva—Larvæ enormous Eaters—Growth of Larvæ
Chapter III.—Moulting of the Larva.—Escape of Larva from its old Skin—Arrangement of the Hairs—Danger attending the Moult—Colours of Larvæ—Influence of Sun-light—Curious appearance of the Coats of Larvæ—Larvæ like Twigs—Singularly coated Larva
Chapter IV.—Respiration of the Larva.—Experiment with Larvæ—Insects do not breathe by their Mouths—Breathing Mechanism of Larvæ—Spiracles—Aquatic Larvæ—Inhabitants of the Ditch and Pool—Rat-tailed Larvæ—Remarkable Organ—Chameleon-Fly Larva—Larva of the May-Fly—Their under-water Cells—Singular organs of Respiration—Complete Armour of Dragon-Ely Larva
Chapter V.—Means of Defence of the Larva.—Leaf-dwelling Larvæ—Larva clad in Rags—"Hickory-horned Devil"—Larva with a Squirt—Shaggy-coated Larvæ—Frozen Larvæ—Dwellings of Larvæ—Remarkable Australian Larva cases—Larvæ in Winter
Chapter VI.—Preparation for a Change.—Age of the Larva—its attempts at concealment—Cocoons of Larvæ—Silk-Worm Cocoon—Extraordinary precaution of a Larva—Case of Bark-skin—Anecdote of a Larva—Suspension of the Larva, horizontally and perpendicularly—Larva of Meat-Fly—Last action of the Larva
PART III.—THE PUPA.
Chapter I.—The Transformation.—Meaning of the word Pupa—Various names of Pupæ—Process of the change—Remarkable feat of a Pupa—Time occupied in the Change
Chapter II.—What is a Pupa?—Characters of a Pupa—Active and Inactive—Dissection of a Pupa—Contents of Pupa-case—Singular Pupa—Goedart's strange Representations of Pupæ—Pupæ from Surinam—Colours of Pupæ—Aurelia and Chrysalis—Ground Pearl
Chapter III.—Respiration of the Pupa.—Spiracles of Pupæ—Anecdote from De Geer—Air-Cell under Water—Difficulty of the task—Pupæ with an Air-tube
Chapter IV.—Varieties and Age of the Pupa.—Different kinds of Pupæ—Age of the Pupa—Pupæ hatched in a Hot-house—Butterflies in Winter—Pupæ hatched by a Hen—Glass Eggs—Influence of Warmth and Cold—Dreams of Immortality—Réaumur's mistake—Varnishing Pupæ—Preservation of Eggs—Falling of the "Manna"—Final changes of the Pupa
Caddis-worm—Singular escape—The Gnat—A
Chapter V.—The Great Change.—An Insect Prisoner—Escape of the Cossus—Escape of a Fly—A guide-line to the Captive—Cocoon of Emperor Moth—Escape backwards—Chemical solvent—Escape of Ants—Huber's Ant-hill—Assistant Ants—Aquatic Insects—The time of Peril—Blood-Worms—A curious spectacle—The Dragon-Fly—Phenomena of the Change—The Insect new-horn—Curious facts about Pupæ
PART IV.—THE IMAGO.
Chapter I.—The New-born Perfect Insect.—The Resurrection—Meaning of the word Imago—Curious aspect of New-born Insect—Conclusion of the Dragon-Fly's History—Structure of a Wing—how expanded—Deformed Wings—Exception in the Ephemeræ—Dance of the Ephemeræ—Insects without Wings—Showers and Stains of Blood—Aphis-Lion Fly—Insects in the Imago state do not increase in size
Chapter II.—The Structure and Organs of the Imago.—Anatomy and Physiology—Insects have not Bones—Leather-coated Jack—The Head and Thorax—The Eyes—simple and compound—Wonders of an Eye—Anatomy of the Eye—Immense number of Eyes—Remarkable Provision—Experiments on the Eyes of Bees—Beauty of the Eyes—The Antennæ—their Function, perhaps the Nose—Insects Weather-wise—Insects in Rain—Organs of Speech—Anecdote of Bees—Various Functions of Antennæ—The Mouth in Insects—Parts of the Mouth—Spiral Tube of the Butterfly—Taste and Smell in Insects—The Trunk—Wings—Membranous—Scale covered—Wing-Cases—Experiments on Flying—Painted Wings—The glory of the Butterfly—The Legs of Insects—Cleanliness of Insects—The Water Boatman—Kangaroo Beetle—The Abdomen—The Sting of the Bee—Insect with a Leg in its Tail
Chapter III.—Respiration of the Imago.—Experiments upon the Breathing of Insects—Chloroform—Coal-gas—their Effects—Contest between a Spider and a Blue-Bottle Fly—Air-Pipes of Insects—Multitude of Air-Tubes—Circulation of Blood in Insects—An Insect's Pulse
Chapter IV.—Food and Death of the Imago.—Vegetable Eaters—Carnivorous Insects—The Tigers to Insects—Fasts of Insects—The Last Duty—Insect Forethought—The Creator's Wisdom and Love—God does not despise Little Things
ILLUSTRATIONS.—DIRECTIONS TO BINDER.
| Egg-rafts of the Gnat | [1] |
| Ferocious Larvæ of Dragon-Fly | [79] |
| Insects escaping from the Pupa condition | [213] |
| Evening Flight of Ephemeræ | [307] |
THE
LIFE OF AN INSECT.
THE NEST
To look at a house-fly as it performs its figure-of-eight dances in the air of our rooms, or as it buzzes against the window-pane, vainly endeavouring to dash its tender body through the firm and clear glassy wall—to mark how soon it comes into existence, and how soon its little day of life is gone—one would say it is a foolish and trifling thing to write the history of an insect's life; but any one who would thus speak must be ignorant of that which he declares to be folly and trifling. He cannot know the miracles of skill that insects, insignificant as they seem, are capable of performing; nor the astonishing lessons of wisdom which even man may learn from these minute and short-lived beings. So long as we are ignorant of any part of God's creation, we may very probably think light of it; but when we come to inquire into the things we have formerly despised, and will give a patient attention to what we before thought beneath our notice, the tone of our remarks will greatly alter. Now, we shall find in the meanest things formed by the Divine hand inexhaustible themes for wonder and praise, and innumerable proofs that the great Almighty power which built our round world, and countless worlds besides, which fixed them with a firm decree in an appointed course, has not been less displayed even in the formation of a tiny insect, which is this hour alive, and the next lost to being.
The telescope shows us what God has created in the innumerable millions of stars and suns which every clear night look down with gentle beams upon the earth; it shows us that the earth on which we dwell, compared to the worlds by which it is surrounded, is as a grain of sand to a mighty mountain. But the microscope, on the contrary, shows us what is almost more wonderful even than this; for it shows us that though the High and Lofty One who inhabits eternity has created all these vast systems of suns and stars, yet he has not thought it beneath Him to chisel the egg of an insect or to adorn the coat of a tiny caterpillar. Well might we pause and ask as we look now through the wonder-revealing tube of the microscope and then through that of the telescope—Was it not a greater evidence of power and wisdom to create, clothe, organize, and endow with the powers of life, a little atom which we can detect only by means of a powerful microscope, than to form even a great and mighty world? For our part, then, we think an insect's history as much a display of the wisdom and infinite power of the Creator as the history of such an enormous body as is the sun, or any of the large planets belonging to our system. However humble be the object which God has seen fit to create, let not any one think it beneath him to examine. The poet Thomson has written some pretty lines which we shall venture to transcribe, which, with far greater beauty of language than we can pretend to, set before us the same train of thought:—
|
"Let no presuming impious railer tax Creative wisdom, as if aught was formed In vain, or not for admirable ends. Shall little haughty ignorance pronounce His works unwise, of which the smallest part Exceeds the narrow vision of her mind?" |
Animals, birds, reptiles, fish, and plants, have had their biographers, and ponderous books have been written to give us an introduction to their various families: so also have insects; although despised by many, they have been highly esteemed by a few; and if honours went by the size of books written about them, it might perhaps be shown that the insects can boast of great and closely-printed books taken up with nothing else but an account of them and their doings.
Perhaps there is another feeling about insects which ought to be mentioned beside the feeling of contempt; that is, the feeling of aversion. A great many people, ought we to write? a great many ladies and children, are ready to scream, and take to their heels if they see a poor "black beetle," racing in terror of his life for fear of them, and as both parties are equally frightened of one another it becomes very difficult to manage a reconciliation between them. At the sight of spiders some people are ready to faint away, and to see a little caterpillar creeping along with his magnificent coat of parti-coloured hairs, and with that funny gait which it is quite ludicrous to behold as he binds himself into a loop and walks after a fashion like no other earthly being, is enough to make their hair stand on end and their flesh to creep!
Death's-head Moth.
Sometimes insects are the innocent causes of alarm even to nations. Thus there is a peculiar kind of moth, upon the back of which there is very distinctly marked the appearance of what is vulgarly called a "death's head," its name being the death's-head hawk moth, represented in the adjoining cut, which was once the cause of the greatest terror to a number of persons. It was in Bretagne that a large flight of them suddenly made their appearance; at the same time a dangerous epidemic disease fell upon the inhabitants; the awful look of the poor insect, together with its strange supernatural noise, filled the ignorant people with alarm, and the disease was considered to be actually caused by the moths. Another insect, the church-yard beetle, which is of a jet black colour, is related by the great Linnæus as producing the most alarming feelings upon the minds of the superstitious and ignorant among the peasantry of Sweden.
The death-tick beetle has also a terrible reputation for frightening people. This little creature takes up its abode in decayed wood, and thus frequently makes the bed-post its dwelling-place, or ensconces itself in the wainscot of an old room. Now, when, as some entomologists tell us, it wants to give a signal to its mate, the insect begins hammering with all its might at the side of the wall, or knocks upon its little floor until the noise is heard, and the mate then begins to hammer, both producing for their size a tremendous noise, but in human ears not sounding louder than the tick of a large watch. The poor invalid, as he lies in bed perhaps very nervous and unable to bear loud conversation, hears the noisy insects knocking one to the other, and immediately his mind is filled with fears of the most groundless kind, which the nurse, if she is one of the old school, is sure to confirm by telling him that this ticking is the death-watch.
Death-watch Beetle.
All this is not only very weak and foolish, but when it reaches the degree to which we have here referred, it is also very wrong. As to the death's head hawk moth producing disease or foretelling death and famine, as it has been said to do, how weak and credulous must they be who draw such omens from a mark on an insect's head; and how dishonouring is it to the all-wise providence of God to imagine that he would suffer such a ridiculous emblem to have any such actual signification! The little beetle which produces the ticking sounds was caught by Dr. Derham one fine sunshiny day, tapping as loudly as it could on a piece of paper in a window; he examined the little creatures and kept them carefully, and he states that during the whole of one summer they scarcely ever ceased tapping night and day. Birds have their calls to their companions, and animals have theirs, yet we do not draw from these the wild supposition that they foretell death or such like disasters. Why, then, should the love-tap of an insignificant beetle have received such an interpretation? It is hard indeed to tell.
Now all these feelings about insects, contempt, abhorrence, and terror, arise in one common cause, and that is ignorance. A very small acquaintance with the contents of the little work upon which we are now entering, would suffice to dispel them all. It may be, perhaps, difficult to overcome what is called a "natural aversion" to any object, especially to an unfortunate insect; but when it is overcome, and when we learn, for the first time, all the extraordinary actions, habits, and instincts, of this portion of the great creation, admiration will take the place of contempt, and even a humble sort of affection that of the terror and aversion produced by them before.
With the reader's permission, then, we will proceed to take him with us as we describe the various stages of the Life of an Insect, from the egg up to the perfect being. It may be, however, just necessary to premise that in so doing we shall not give anything like the history of an individual insect, such, for example, as a fly or a bee; but shall describe in order some of the most interesting phenomena connected with insect-history and transformations generally. Whither, then, must we go to watch the awakening of life in the insect? We might ask the reader's company to
|
——"where the pool Stands mantled o'er with green, invisible Amid the floating verdure, millions stray." |
Here might we point to him that wondrous and exquisite structure, the life-boat of eggs, floating[A] securely on its silent surface, or anchored, perhaps, to the side of some pond-plant's slimy stem; and lingering here we might in a few days see the little eggs become burst and give exit to a number of minute creatures of great activity. Some of them would be seen twisting themselves about in a most extraordinary manner, and swimming here and there through the still waters. Or we might take him to the depths of the forest, and now, under the bark of some of the trees, now upon their branches, now in little tents of leaves, we could point out many a colony of eggs only waiting for the life-giving influence of spring to burst into life and activity.
But it is better for us to proceed more systematically, and to notice shortly the interesting facts which the science of entomology reveals to us as to the egg-cradles, so to speak, of insects, by which is meant the various localities selected by them for the deposition of their eggs, some of them, as we have mentioned, in the water, some in the earth, some upon plants and trees, and some in mansions made by the insects themselves for the purpose of hatching their eggs.
Let us come, then, and watch the great water-beetle, at the time when the mother-insect is about to commit her future offspring to the care of the waters. She is to be found on fine days, when the sun is going down into a bed of gold, enjoying herself and delighting in the pleasant air of the evening, as she sits upon a plant close by the water's edge; or she may even have taken up her position on a floating leaf of the plant, the clear waters flowing gently beneath her. She has been in the water all day long, and is now just emerged. On other evenings she will take wing, and speed her way whither no eye can follow; but now, she has another and the most important duty of her existence to perform, and her customary evening ramble is not permitted to interfere with its fulfilment. On watching her closely we find her busy at some self-imposed occupation; what is its nature? To discover that, she must be closely and patiently watched. At her tail are a couple of spinning organs, which move from right to left and up and down with great swiftness, all the while a glutinous fluid, which hardens into a thread, being discharged from each of them. With this apparatus the industrious insect is spinning a pouch not unlike the purses which were in fashion before the long ones that ladies knit came to be adopted. This purse is three quarters of an inch long; it consists outside of a tissue, like parchment, which is quite impervious to water, but is lined inside with the most beautiful, light, downy material possible, which is as white as snow. There is a sort of little horn to this pouch, which admits the air, but the opening to which is protected by a layer of cross threads, which excludes the wet. In three hours of patient toil this beautiful cradle is completed. The water-beetle then safely secures it from being carried away by the waters on which it floats so buoyantly, by fastening it by cables to the neighbouring plants. Here safely moored it rests until the eggs are hatched, soon after which the little creatures within escape into the waters out of the ark, which has, during the period of their infancy, safely preserved them from every danger, both of water and wind.
The proceedings of the common gnat, our summer tormentor, are no less interesting and instructive. Her actions have been closely watched by the great Réaumur, and are detailed by him with very striking accuracy. They require, perhaps, sharper scrutiny than most of our readers are in the habit of bestowing upon the actions of insects, but they well repay a patient and attentive observation, and subjects for the examination may easily be found at the side of any pool in summer. The following is an outline of the difficulties the insect has to contend with in depositing her eggs. First, they must be hatched on the water; but, 2d, her eggs are heavier than water, and will therefore sink if dropped into it one by one; and, 3d, the eggs are so small and of so peculiar a shape that it would be difficult to make them stand upright on a solid surface; far more so then, on the water. A human ship-builder would be probably sorely puzzled to find out how to overcome these difficulties, and of such materials how to construct a floating raft; nay, a raft which cannot by any means be made to sink. The insect has, however, been instructed by a Greater and Wiser than man, and she solves the problem in a manner well calculated to excite our admiration and praise. Fixing herself by her four front legs upon a leaf or twig floating on the surface of the water, she stretches out behind her the two hind legs, and crosses them over one another somewhat in this manner
. In the triangular space thus formed she purposes to construct her boat of eggs. Now, all things being ready, just where the crossed legs meet she places her first egg, which is covered over with a thick glue. By the side of this she places another, and again another, so that the three are, by means of the glue which covers them, united together, and will, consequently, preserve the upright position, as there is now a sufficiently broad base of support for them to rest upon. To these she diligently adds egg to egg until she has sufficiently formed the shape of her boat; after which she uncrosses her legs and places them quite straight, so as to shape the sides of the boat. When a sufficient number of eggs have been thus glued together, the number varying from two to three hundred, the gnat considers her task as ended, and wings her way from the pool, abandoning her ingenious structure to the mercy of wind and wave, although not without the security of knowing that neither wind nor wave could commit serious injury upon it.
"In shape," write Messrs. Kirby and Spence, "this little boat pretty accurately resembles a London wherry, being sharper and higher, to use a nautical phrase, fore and aft; convex below and concave above; floating, moreover, constantly on the keel or convex part. But this," they add, "is not all; it is, besides, a life-boat, more buoyant than even Mr. Greathead's. The most violent agitation of the water cannot sink it; and what is more extraordinary, and a property still a desideratum in our life-boats, though hollow it never becomes filled with water, even though exposed to the torrents that often accompany a thunder-storm. To put this to the test I yesterday placed half a dozen of these boats upon the surface of a tumbler half full of water. I then poured upon them a stream of that element from the mouth of a great bottle held a foot above them, yet, after this treatment, which was so rough as actually to project one out of the glass, I found them floating as before upon their bottoms, and not a drop of water within their cavity."
Rubbish Towers of the Sand-Wasp.
Some insects make the homes of their young in the earth. Of these, the insect called the sand-wasp forms, perhaps, one of the most interesting examples. This insect selects generally a hard sunny sand-bank for the excavation it is about to accomplish. Armed with a pair of powerful jaws, by means of which the insect can break off good-sized fragments of the rock she is about to mine, she sets to her arduous undertaking with a bold heart, and it is not long before a tolerable cavity is scooped out. Many of our readers have seen the manner in which human miners proceed when they are forming a hole in a lime or other rock, for the purpose of blasting, and must have noticed that they are in the habit of using a little water, in order to facilitate the boring operation. We are all, also, familiar with the tale of Hannibal chemically softening the Alpine rocks by means of vinegar. The little insect in question has been instructed by the great Creator also to adopt a means of shortening her labour, for it has been observed that she moistens the rock by letting fall a drop or two of fluid upon it from her mouth. By this means her work goes on rapidly. The rubbish soon begins to accumulate. It will be scarcely conjectured what this patient labourer does with it. Were we to look narrowly at the sand-bank which such wasps frequent, we should find on its surface a number of curious little projections like horns, rising from the surface. These are towers built by the sand-wasp of the pieces of rubbish which she scoops out of her mine. She cements them together, and, instead of throwing them away, she lays the masses in regular order until they have assumed the appearance here shown. It has been supposed she does this with a view to keep out enemies and to keep her progeny cool; just as in a tall house the cellar is its coolest apartment, so the height of the tower in question seems to be an additional protection against the rays of the scorching sun. After it has deposited its egg at the bottom of the excavation, the sand-wasp sets out on a foraging expedition, and hunts about until she finds certain green caterpillars. Seizing upon one of these she flies with it to her mine, and then returns for more prey. After collecting about a dozen of these helpless beings, fixing them so that they are hopeless captives inside her dark prison, she bids farewell to the egg, for the future well-being of which she has thus assiduously provided. She takes down her tower of stones, and, with the materials which composed it, fills up the entrance to the cell, thus shutting in both the prisoners and their future devourer in a common dungeon, there to await the changes which time will inevitably bring about.
Let us speak now of eggs carefully deposited by other insects in galleries and excavations made into timber. The insects which thus act have been called by the fanciful title of carpenter-bees, in allusion to the drilling process by which they penetrate the wood. A highly interesting spectacle it is, in truth, to see one of these pigmy carpenters at her work, and, fortunately, some of the species are not very uncommon in our gardens. Spring is the season when she commences her labours. She reconnoitres about for a proper piece of timber for some time, and exhibits great discrimination in the selection of a suitable place for establishing herself and for the nurture of her progeny. Strange to say, she will not select living wood, such as the trunk of a tree, but generally prefers wood which has already begun to decay, as if fully aware that such wood was likely to give her much less trouble in boring than any other. She also selects a piece of wood placed in some sunny and genial position, with a view to the development and comfort of her progeny. This important point being settled to her mind, she next sets about the work. Well may Réaumur exclaim, "Truly the labour she has undertaken demands strength, courage, and patience!"
Carpenter-Bee.
Mandibles of the Carpenter-Bee.
The violet carpenter-bee is, perhaps, the most interesting example we can select. She begins by cutting out with her strong jaws small portions of the timber, and soon forms a little hole, which looks downwards and inwards into the wood. She then alters the direction of her drilling, and now perforates the timber perpendicularly downwards, and in a parallel direction to the sides of the wood. Long and hard does she thus labour, until she has actually scooped out a tunnel in the timber a foot or so in length, and half an inch in diameter. Sometimes she will drill several of these beautiful galleries in the wood. The task, however arduous, never seems to weary her; impelled by a heaven-bestowed influence, she works strenuously and cheerfully for weeks, or even sometimes for months. Our readers may be interested to know what she does with the saw-dust. If they can but get an opportunity of watching her they will soon see her mode of dealing with it. Standing by the side of the wood she is drilling, and keeping our eyes stedfastly fixed on the hole, we shall presently observe her head emerging from it, and immediately after she is seen to shovel out a little heap of the dust, which accumulates on the ground beneath into a pile. When her galleries are finished her labour is yet far from accomplished. She has now to deposit her eggs, and make provision for the prospective wants of her young ones. Now, her eggs must not be piled together, nor be scattered about in the same cavity. The larvæ which are to be produced by them must each live in separation from the others. How is this fresh difficulty to be overcome? The insect soon supplies us with the answer. She has not forgotten her heap of saw-dust. She first deposits an egg at the bottom of the tunnel, and then away she flies to the fields for a load of the fine yellow dust of flowers, called pollen, and also for honey. She mixes these up into a nice little mass of pollen-bread, or cake, which is intended for the food of the larva, when it comes out of the egg, and then piles it up in the gallery just over the first egg. She then, at a height of about three quarters of an inch, plasters a layer or ring of saw-dust made by her into a sort of mortar, and adds to this another and another ring of the same material until the ceiling is quite complete, and the cell thus formed is shut off from the rest of the excavation by a circular plate of this substance, which effectually excludes all intercourse between the occupants of this wooden nursery. Having completed this cell she proceeds in the same way to lay an egg, and to provide a store of food, and, finally, to close in the rest of the gallery, until she has subdivided it into ten or twelve separate apartments. The appearance of the circular ceilings formed on these ingenious principles is exhibited in the engraving annexed.
Cells of Carpenter-Bee.
Ceiling-plate.
Section of Cells, showing the ways of escape.
One of the most striking facts in connexion with the proceedings of this little creature has yet to be brought under our notice. It will be readily admitted that the first egg deposited at the bottom of the gallery will be the first, in point of time, that will be hatched, and, consequently, the first to require to make its escape from the wooden prison-house of its birth. How is it possible for this to take place, when above the poor prisoner's head are ten or twelve cells full of other occupants, and each shut in with a hard ceiling and floor? By referring to the figure, we obtain a clue to this enigma. It is here seen that there are holes which communicate with the tunnel within. The uppermost of these holes was the one by means of which the tunnel was first formed, but the two lower ones have been expressly formed by the carpenter-bee to provide against the dilemma in which her young would otherwise have been placed. They form as it were posterns or back doors by which, when the insect is perfected, it is easily enabled to make its escape. Singular, indeed, it is, that the insects, previous to passing into their last transformation, arrange themselves with their heads downwards, so that every one of them generally emerges at the so-called back-door of the mansion.
There are many similar instances in natural history of the manifest wisdom and forethought of the Creator of all things, visible and invisible, but we may safely say there are not many which show it in so clear and striking a point of view as this. It is to be remembered this industrious insect in the arrangements in question does not act from past experience. She never saw her young brood, nor could learn of herself their wants and dispositions, yet her plans for their welfare are as admirably contrived as if she had brought up generation after generation under her own eye, and had learnt wisdom by the lapse of years. Plainly, therefore, her actions are all directed by an impulse given her from God, and we may well exclaim with the wise king of old, it is God who "doth instruct her to discretion, and doth teach her." Altogether, what an example of patience and cheerfulness in her labours, and of admirable wisdom in their performance, is presented to us by this little sketch of the history of the carpenter-bee's nest!
Among the birds discovered in Australia, is one called the Bower-bird, from its fondness for making a bower, which it ornaments in a very pretty manner. Other instances of a somewhat similar kind could be mentioned, tending to show that some of the lower animals are as fond of decorating their dwellings as we are ourselves. There is, however, in the insect world, a little creature which has been called the tapestry-bee, which adorns the place where its progeny is to be born with a tapestry as novel as it is elegant. The great entomologist whom we have before quoted, thus describes his first discovery of this interesting fact:—"In one of my rambles, which had led me through several lanes, and in the course of which I had frequently stopped to examine the little tunnels pierced in the earth by various insects, my companions began to engage in the same occupation with myself; one of them at length perceived, and pointed out to my notice, a tunnel which had some peculiarities of appearance not possessed by the others we had seen; its interior seemed to be painted with vermilion. A small twig was immediately gently pushed into it, and with a knife we carefully removed the earth which surrounded it, taking great care not to injure the walls of the tunnel. When we had uncovered it sufficiently, it was found that the little stick was buried in a tube made of the leaves of the field poppy.
The Tapestry-Bee and its Cell.
"I need scarcely say, that during the remainder of our ramble we were exclusively occupied in searching for similar holes. It is a common observation, that when a fact, which has not hitherto been recognised among those presented to us in nature, is once caught sight of, we are almost sure to see it again and again, until we wonder how it could have been that it was never noticed before. We therefore now found other holes, leading to similar tubes, formed in the same manner of the flowers of the red poppy. Altogether, before returning home, we found seven or eight of them; and since that time, I have found them in all their different stages." These elegantly decorated apartments were subsequently found to belong to the tapestry-bee.
Poppy-flower cut by the Bee.
This bee, in forming the future abode of her young, begins by scooping out a burrow in some pathway, which she bores to the depth of two or three inches. She then smooths the walls of this cavity, and all being now ready for putting up the hangings, she betakes herself to the fields, and alights upon some fresh-expanded poppy flower, just displaying its crimson cheeks to the light of day. Here she quickly plies the scissors which she has been armed with for this purpose, and in a very short time cuts out of the bright petal on which she rests, a smooth portion of a definite size. She then returns home, and, by means of the scissors and her legs, she cuts and smooths the piece until it lays quite flat upon the bottom of her cell. This done, she flies for more, and in a short time, could we peep in, we might find her mansion all over-spread with tapestry, more bright in colour, and more delicate in point of finish and texture, than human art can by possibility produce. The apartment being thus not only decorated, but rendered, both to the eye and senses, warm and comfortable, she then stores up in it a quantity of pollen and honey, until she has filled it to the height of half an inch, when she deposits the egg, for whose wants and, as we might say, even luxuries, she has thus elegantly provided, folding some of the hangings carefully over it. The remainder of the cavity is filled with loose earth. We have taken it for granted, in this account, that the insect really takes a pleasure in the brilliant colours with which she ornaments her cell; but it is only right to say, in addition, that we have, of course, no positive proof that such is really the case. For aught we know, her motives may be very different; it is, however, an amusing way to consider these actions, be the explanation of them what it may.
Finished Cell.
We fear, however, we dare not promise our readers the same success as that which attended M. Réaumur and his companions. It has been thought, that this interesting insect is not a native of our island, and it is certain it has not been commonly observed amongst us; but Mr. Rennie, in his work on Insect Architecture, says, that at a beautiful sea-bathing village in Ayrshire, he once found in a footpath a great number of the perforations of the tapestry-bee. At all events, they deserve looking for.
Leaf tubes.
Although we have, perhaps, lingered long enough over the insect cradle, we must spare room for one or two more remarks on this subject, and it were almost a shame, while speaking thereon, to omit a notice of one of the most elegant cradles of all—one made with rose-leaves! As Réaumur's account of the manner in which he first became acquainted with these egg depositories is very pleasantly written, we shall extract the substance of it from his work. It was one day in July, 1736, that a gentleman of rank, accompanied by his suite and his gardener, who was in a state of great alarm, waited upon an eminent naturalist in Paris. The gardener had left his master's country-seat, near Rouen, to proceed with all haste to the metropolis, in order to communicate to his master the terrible tidings, that his ground was bewitched! He had the courage, however, to pick up the spells, or charms, which the sorcerer had placed in the earth, and to carry them to his master, in full belief that they were sufficient to convince all the world of the reality of the enchantment. He had, indeed, in the first instance, taken them to the parish priest, begging his counsel, and both came to the same conclusion—that, without doubt, the garden was now enchanted ground! When the gentleman saw the little things his gardener called charms,—which are here represented,—he was much perplexed, although his good sense led him to ridicule the idea of the bewitchment of his property by such means. He applied to his medical adviser for a solution of this problem; but, alas! he was no entomologist, and could not enlighten him; but he directed him to the naturalist of whom mention has been made, and whose name was M. Nollet. On being admitted to the presence of this gentleman, the terror-stricken gardener hastily put on the table the little rolls of leaves he considered to be spells, and which had been made, with some evil design, as he doubted not, by the malevolent hands of some sorcerer. Fortunately, M. Nollet had in his museum some rolls of leaves formed with equal art by beetles; he produced them, and showed them to the affrighted man, assuring him, that, without doubt, they had been formed by insects, and that it was therefore highly probable that the rolls in question were the productions of some other insects of a different species. The gardener looked incredulous, being apparently unwilling to give up his alarm, until M. Nollet, greatly to his horror, took up one of those little leaf-rolls which had caused him so much uneasiness, and carefully unfolding it, drew from thence a fat little larva. The moment the gardener saw the little creature, his fears and troubled aspect vanished, and an air of cheerfulness spread over his face, such as one might imagine as the result of deliverance from some fearful peril. The only reward M. Nollet would receive from the poor man for thus dissipating his cares and fears was, that he should leave the leaf-rolls with him, and, collecting more of them, should send them to M. Réaumur's address, for him to examine. This little anecdote affords us a good illustration of the connexion of superstitious fears with ignorance on points of natural history, and sets before us, in well-relieved contrast, the foolish terrors of the unlearned gardener with the collected bearing of the learned naturalist. Would that this anecdote stood alone in the records of natural history! We have already seen that it does not; and that the most groundless apprehensions have taken their rise in the most innocent and trifling of natural causes.
The Bee with a leaf cut.
By and by, after a little careful investigation, the true artificer of these spells was discovered, and proved to be a lowly insect, which has been since called the rose-leaf-cutter bee. On closer examination, these rolls of leaves,—which are almost as long and as large as a tooth-pick case,—were found to be made up of six or seven cells, each separate from the rest, placed end to end, and covered with a common coating of leaves. The manner in which the roll is formed is as follows:—The insect sometimes makes a perforation in decayed wood, sometimes in the well-trodden earth of a footpath; this she drives to the depth of, perhaps, nine inches, and she then proceeds to hang this apartment with its green tapestry,—for it must be understood, it is not the leaves of the flower, but of the stem of the rose-tree,—or, in other words, the green leaves, that she selects for this purpose. The insect alights upon what she considers to be a suitable leaf, and begins with her sharp jaws to cut out a piece of a crescent form from its edge. When she has cut, perhaps, half-way round, or rather more, she sets her wings in motion, so as to keep her balanced in the air, lest she should drag away the half-cut piece before it was properly divided from the leaf. When cut, she places it in a perpendicular position between her legs, and flies away with it to her cell. She then simply folds it into a proper form, and overlays the cell walls with this leafy covering, not using any cement to make it retain its form, but relying upon the natural elasticity of the leaf to keep it close pressed against the wall in the manner in which she places it. Repeating this process several times, she finally completes each cell with exquisite art and care, and taking the precaution of arranging all her joints and seams so that they shall not present themselves in the same place, but covering them over with pieces of leaf, so as to strengthen them, and in many other respects exhibiting an amount of mechanical and mathematical skill never sufficiently to be admired, she now deposits the minute egg in it which is to become the toilsome, busy, patient, and clever being,—the full-grown insect of her own species. Mindful of its future wants, she then compounds a delicate mass of pink conserve, which she collects from thistles, and subsequently stops up each cell with thin pieces of leaf, as exactly round as if they had been cut out with a punch, or by means of some mathematical instrument.
Réaumur says he often, in the month of May, on looking at his rose-trees, detected these insects at their work; all he had to do was, to stand and patiently watch by the side of a tree, the leaves of which exhibited the singular marks made by this insect. Many times have the same appearances arrested our attention, and without doubt that of the reader. The spectacle of insect ingenuity which it affords well promises to repay a little exertion in endeavouring to find out the nest to which the pieces are conveyed, and some neighbouring post or footpath will probably discover it to us after a sharp scrutiny. Sometimes the insect makes a bad choice of a leaf; it may be, perhaps, too tough for her; but she soon discovers her mistake, and leaves it, half cut, to seek a better on the same branch.
A Rose-branch cut by the Bee.
The nest formed by a species of moth for depositing her eggs in, is one equally interesting to describe. From the resemblance of her actions to the well-known account of those of the eider-duck, whose maternal love strips her breast of down for the purpose of protecting her eggs, we might almost venture to call this moth the eider-moth, were it not that it is known under another and far less appropriate name—the gipsy-moth. Indeed, in the care of the insect the mother's love is, as we might say, even more powerful than in the bird; for, while the latter has the pride and pleasure of seeing her little ones grow up around her, the poor insect, after stripping herself of her own soft, warm down, thus testifying her love to her offspring even to death, presently expires. The insect in forming her nest first plucks off, by means of a singular instrument, like a pair of tweezers, with which she is provided, a little portion of down from her body; seated upon a tree, she attaches this to its trunk, and then deposits an egg in it, which immediately adheres to the down, and becomes coated with it. The remainder of her operations, until she has deposited the entire number of eggs, are but repetitions of the same actions. When the process is at an end, she begins to form a regular tile or covering to her nest, and this she effects with a degree of skill not unworthy of the most consummate thatcher. She arranges the hairs of the down just as the thatcher does his stems of straw for the cottage roof, so that they all slope downwards, resembling much the smooth pile of a hat. By this arrangement of the down, it is next to impossible that in the most drenching shower the eggs, warmly wrapped up within, should be wetted or otherwise injured, and the down itself, being a material which, as we all know, is a non-conductor, preserves the eggs from the influence of the most severe frosts. In shape, this nest of eggs resembles a skittle, or a truncated cone, the broad end downwards. The engraving represents this form, and also shows the insect at work constructing the nest.
The Nest of the Gipsy-moth.
Eggs of Lackey-moth. (Natural size, and magnified.)
Let us now pass on, to mention, that many eggs are deposited without any special protection of the kind we have described, and without what would be with propriety termed a nest. A moth, called the lackey-moth, frequently ornaments the young twigs of trees in our gardens with exquisite bracelets of glistening white eggs, looking like beads. From two to three hundred of these eggs are glued on by the insect around the twig, by means of a tenacious waterproof cement, and are arranged with an accuracy of the most marvellous character, in a close spiral line upon the twig. The cement employed by the insect in uniting her eggs, and in varnishing them over, is so hard as to serve the purpose of a covering, which admirably casts off the rain, and preserves the eggs free from injury by the elements all the winter long. Many eggs are simply glued on irregularly upon the stems and leaves of plants, their shells or outer coating, together with the protecting varnish, being sufficient to preserve them from the inclemencies of the weather; but some are piled together with the most striking regularity, in regular columns of eggs.
In addition to these, it is proper to state, that some insects lay their eggs in the body of the young of others. Of these, those which are most dreaded by the insect tribe are the little but terrible flies, called Ichneumons. They are so called because in their actions they agree with the popular account of those of the ichneumons of Egypt, which were venerated as the destroyers of the eggs of serpents and crocodiles. "Such," say Messrs. Kirby and Spence, "is the activity and address of the ichneumons, that scarcely any concealment, except perhaps the waters, can secure their prey from them; and neither bulk, courage, nor ferocity, avail to terrify them from effecting their purpose. They attack the ruthless spider in his toils; they discover the retreat of the little bee, that for safety bores deep into timber; and though its enemy, the ichneumon, cannot enter its cell, by means of her long ovipositor (organ for depositing the egg), she reaches the helpless grub, which its parent vainly thought secured from every foe, and deposits in it an egg, which produces a larva that destroys it. In vain does the destructive cecidomia of the wheat conceal its larvæ within the glumes that so closely cover the grain; three species of these minute benefactors of our race, sent in mercy by Heaven, know how to introduce their eggs into them, thus preventing the mischief they would otherwise occasion, and saving mankind from the horrors of famine. In vain, also, the cynips, by its magic touch, produces the curious excrescences on various trees and plants, called gulls, for the nutriment and defence of its progeny. This parasite insect discovers its secret chamber, pierces its wall, however thick, and commits the destroying egg to its offspring." In vain, also, might we add, does the sand-wasp excavate her deep cell for her young ones; for when once the ichneumon has discovered the retreat, the destruction of the young larvæ is inevitable. She pierces through the defences piled over the mouth of the cavity, with all the precision and patience of a higher creature, and rests not until she has thrust down her long ovipositor, and placed the egg in the body of the helpless prisoner below, when she flies away, confident that the days of her victim are numbered, and having thus doomed him to be eaten up alive! The common caterpillar, which, by its ravages in our cabbage rows, makes itself a little too familiar to us, has a fierce enemy in these flies; they dart upon it, pierce its body in many places, laying an egg in each wound; these in due time become hatched, and eat their way out of the body of the poor caterpillar, who soon dies, while the larvæ, after undergoing their proper transformations, become perfect insects themselves, fully equipped to proceed to the same work in some other individual of the caterpillar kind.
To man, this ordinance of the Creator, that some insects should lay their eggs in the bodies of others, and so destroy them, is of inestimable benefit. It is quite impossible to imagine what would be the result, were weevils, caterpillars, and such like insects, to be permitted to multiply without a check. Produce of all kinds would soon be consumed, and the desolations of an universal famine would overwhelm man and beast. But God has been pleased to ordain it otherwise. In proportion to the increase of the destroyers is the increase of those that prey upon and destroy them. Thus, what has been well called the balance of creation is preserved, and by means of the insects in question, conjoined to other causes, is the command to the destroying powers enforced—"Hitherto shall ye come, but no farther."
STRUCTURE AND CONTENTS OF THE EGG.
In the past pages we have now considered shortly the various methods of depositing the eggs of insects, and have seen that the nursing place where the young being is produced, differs widely both in point of its position, and of the external circumstances which variously affect it. For some are the deep-bored galleries in timber; for some, the hard-wrought tunnel, scooped by an insect out of a rock; for some, the ingeniously-formed boat or raft, which is to carry its cargo of life buoyant on the dancing waters "all the days of its appointed time, waiting until its change come;" for some, the cell of earth lined with painted hangings, exquisite in make and colour; for some, the little leaf-case, curiously folded together; but for others, none of those works of insect art are provided; they, hid in a rain-proof covering of varnish, lie open to every eye, or scattered here and there on all and every kind of flower and herbage, lie at the mercy of every wandering foot. While, lastly, others are buried with a cruel yet merciful art, in the bodies of myriads of unsuspecting members of the insect community, lying, like the seeds of evil in the heart of the infant, dormant awhile, but destined to grow with its growth and to strengthen with its strength.
The time has, therefore, now come that we should speak a little more particularly upon the nature and character of the eggs of insects. The shape of an insect's egg, although frequently something of an oval in its outline, is very various; in fact, were the egg of some peculiar species placed in the field of a microscope, probably not one general observer out of a hundred could in the least imagine what the object at which he was looking really was. Sometimes they are oval and exactly resemble the form of the egg of the bird; but in other instances they are of the most irregular and fantastic appearance. Some look like pill-boxes tied over and down their sides with string; others look like tiny flasks, with many raised ribs upon their surface; others have lids and springs. The gnat's egg resembles a chemist's phial, or one of the new bottles for holding aërated waters; and those of the dung-fly have two little pieces sticking out at the top on each side to prevent them sinking too deep into the matter upon which they are deposited.
Various forms of Eggs.
Eggs of Lace-winged Fly.
The eggs of some insects strikingly resemble the little shells like turbans with which we are most of us familiar. A very singular variety of egg which has often caused much perplexity to naturalists is the egg of the lace-winged fly. Réaumer says, "I had observed them several years without actually knowing what they were. Others as well as myself had noticed that on the leaves and twigs of many trees were a number of minute stalks placed together, scarcely as thick as a hair, their colour was nearly white, and they were about an inch in length; there were sometimes ten or twelve placed in a bunch; the end of each stalk bore a small head of an egg-like or oblong figure. They appeared to me to be fungi, the little head precisely resembling the appearance of moulds as seen under the microscope; but they were larger in size." They were, in fact, the eggs of the fly in question. When the larva escapes from them they have much the appearance of little vases; and the same author assures us that they were once described and engraved by a naturalist as some curious minute flower growing on the leaves of the elder, for which he was unable to account. The representation of them in the cut will enable the reader to form his own opinion as to the difficulty of ascertaining whether they were flowers or the nests of an insect.
Manner of depositing the Egg.
The manner in which these eggs are thus regularly placed by the insect is interesting. Placing herself upon the leaf in the attitude represented, she fastens a thread to the leaf, draws it out in the same way as a spider does her lines, and when it has got sufficiently firm the wise insect then puts forth the egg, glueing it to the extremity of the stalk; this done, she quits it and begins to form another, repeating the same actions until the proper number is laid. Poised on the summit of these slender pillars the eggs are secure from every invader but man himself, and in time there comes from them the larva which is to become the beautiful insect, the "lace-winged fly," in all the elegance of its form.
From what has been already stated, the surface of the eggs of insects, it will be perceived, is by no means in all cases smooth and polished as in the case of birds. Far otherwise. To look at some of them by the help of a magnifying glass we should imagine that they were covered with very fine lace net, others appear as if some clever engraver had been chasing some intricate design upon their surface. The eggs of a species of butterfly are studded over with an infinite number of little knots or tubercles; and those of another are capped at the top with sculptured work disposed in the form of a circular tiling or roof to the egg. Some also closely resemble embossed buttons.
He who has thus adorned these minute objects with beauty of form and carving, has likewise bestowed upon them the most beautiful and variegated colours—colours such as no human art can imitate. But from the small size of the eggs it is difficult to appreciate this beauty in them except when they occur in a mass. The most common tints are white, yellow, and green, but the richer and rarer hues are also to be found among them. Thus, the eggs of a moth are of a beautiful blue colour, banded in the most delicate manner by three zones or rings of brown, the contrast being very pleasing. Another moth, which loves to deposit its eggs in the bark of the willow, produces them tinged with a purple more delicate than ever Tyrian lady wore as the finest produce of the dyer's art. In the deep crevices of the bark of the elm, and only, therefore, to be found by sharp scrutiny, another moth lays eggs of a lovely pink. Messrs. Kirby and Spence write, "We remember once being much surprised at seeing the water at one end of a canal in our garden as red as blood; upon examining it further we found it discoloured by an infinite number of minute red eggs." Sometimes eggs are spotted, and thus resemble the eggs of many birds; and, strange to say, sometimes they change colour in a very remarkable manner; so that, as far as colour is concerned, an observer could scarcely believe that the egg was the same he beheld, perhaps, a few days previously. The eggs of the chameleon fly, as we are told by the gentlemen last quoted, are at first pure white; then change to green, and finally turn to a deep olive-green. Others are at first mouse-coloured, then reddish, and, lastly, black. The eggs of a kind of moth we have seen first of the colour of sulphur, then becoming green, after that rose-colour, and lastly, black. In the instances of the common gnat and silk-worm, similar changes of colour take place. The eggs of the gnat are first white, then green, and finally gray; and those of the silk-worm are in the first instance of a pale yellow, and ultimately take on a violet tint.
Having thus noticed these points in connexion with the Life of an Insect, we are led to that most important of all periods, the dawn of life in the egg, or, in common terms, the period of hatching. But before proceeding to the subject, may we not pause and wonder as we behold the varied manifestations of the Creator's wisdom in the actions of the minute, and, as we often call them, insignificant creatures of whom we have spoken? Should David say, when he beheld the sun, moon, and stars, as the work of a Divine hand, "Lord, what is man, that thou considerest him, or the son of man, that thou regardest him!" And shall not we, as we contemplate the few particulars here set down of the wonders of insect-life, exclaim, with even greater astonishment, "What are these, that thou considerest them?" Let no one then say, that entomology, or any other natural science whose field of study lies chiefly among the minute portions of creation, are profitless sciences, when they can reveal to us such a display of the power, wisdom, and love of God, as is exhibited even in this small portion of the Life of an Insect.
Let us then take up one of these eggs, so minute, but containing within it the rudiments of a being which is in time to assume a form of considerable magnitude, by comparison, and to be adorned with colours richer than art can boast of, and let us examine it on the field of a tolerably powerful microscope. We need not look far for a specimen. In the dark corner of the ceiling in a neglected room, after removing the mass of dust-filled webs that have accumulated there for months, we may find without difficulty a spider's nest of eggs. A more pleasant place to search for insects' eggs is, perhaps, the garden; and if in the crevices of the bark of the trees, or attached to twigs or branches, none can be found, we can almost certainly promise success if the reader will carefully and patiently search the angles of the garden walls, particularly if he has noticed in the preceding autumn many of the beautiful webs of the garden-spider. There, in some sheltered recess, where the pattering rain-drops may be heard, but never venture in, and where few eyes would detect them, may be found little round yellow balls, of the size of a small cherry, made of the most beautiful golden-coloured silk, and attached by a slender stalk to the wall, or perhaps, to a twig. Sometimes they exhibit the more elegant and curious appearance shown in the figure on the next page, resembling an inverted wine-glass or pear.
Nests of Garden-Spider.
On taking our prize in-doors, by the aid of a very sharp penknife we may succeed in cutting it smoothly open, and in turning out some of the delicate eggs which lie warmly covered up at the bottom. Taking one of them up on the point of the knife, and laying it on the microscope-field, we shall be able to see something of the anatomy of an insect's egg.
First, we may notice what seems to be the shell; that is, the outer covering of the egg. This is very different to the hard, calcareous eggshell of birds. It is stated not to contain any lime in its composition as the shells of birds do; for when the eggs of insects are put into very weak sulphuric acid and water, which would act on the lime if it were present in their composition, they are not affected by it. Although, therefore some eggs of insects are very hard: so hard indeed as to resist severe pressure with the nail, they do not owe their hardness, as do the eggs of birds, to any lime in their chemical composition. The outer coat or shell is apparently simply membraneous, frequently varying greatly in thickness, being sometimes as dense and horny as we have mentioned, and at others, so delicate as to burst with the gentlest touch.
Nests of Spiders.
Could we now do, what it is so easy to do with the egg of a fowl,—carefully take off a little portion of this outer shell, we should be able to inspect its contents more accurately. But in the case of most who read this book, this extremely delicate task will prove after many trials probably a hopeless failure. Let us state, therefore, what some expert and talented observers have found within the insect's egg. It appears, then, that although there is both a "yolk" and a "white" in the tiny egg before us, that they are not quite so distinct as in the bird. Yet, they are sufficiently separate from one another to make their differences complete. Probably the reader has noticed in the hen's egg a little round spot in the middle of the "yolk" or yellow portion; from this the future bird is produced. Although from their extreme minuteness it is difficult to detect anything of this kind in the eggs of insects, some observers state they have seen a similar little spot in them also. Thus, M. Herold says, that in the eggs of the very insect whose nest we have robbed, the garden spider, "this little spot can be seen as a minute white point immediately under the shell, and in the middle of its circumference." This was seen by holding it up to the light, and the spot was more carefully examined by gently pressing the contents of a spider's egg upon a watch-glass. Mr. Rennie says, that "the point where the caterpillar originates, answering to the scar in the eggs of birds, we can readily distinguish even by the naked eye in the larger species of eggs, as it lies always immediately under the shell." But it may be doubted whether, without the assistance of some one versed in entomology, many who make the same attempt, will succeed. So much depends in looking at any object upon whether we know what to look for or not, so that things which are as clearly seen as possible by the eyes of the initiated, are not seen at all by any others. To perceive some things in natural history, and many in science, the senses of sight, hearing, and touch, require to be well educated, and they then become apparent enough.
And is this all that we can mention about the structure of an egg? This indeed is all. Can it be possible? Is there no striking and broad difference to mark the nature of the future insect? Is the egg of a spider the same in the number and nature of its parts as that of a butterfly, or the egg of a gnat as that of a beetle? Surely, as we should imagine, there must be some important differences between these, otherwise why such immense differences in the perfect insect? Could any one imagine that a grasshopper and a house-fly, so strangely unlike each other in their perfect forms, originated in eggs to either of which the same description of an insect's egg would accurately answer, and leave nothing out? However great our amazement, the fact is unquestionable. The egg of every insect at first consists of an outer covering, a white, a yolk, and the little spot we have alluded to. We might have thought that in creating so many different species of insects, which differ so surprisingly in form as the insect tribes do, the great Creator would have formed their eggs essentially different too. But, except in the matter of shape, all are originally alike; and the wisest philosopher is unable to inform us of any essential difference in the eggs of insects at first. The eye of God, who knows the end from the beginning, sees some difference inappreciable to the eye of man. He said to this kind, "Be thou thus," and to that, "Be thou different;" but until the time comes when the young insect is much more advanced, it is not possible for us to recognise those marks of variety which His hand has laid upon them from the beginning.
LIFE BEGINS IN THE EGG.
The eggs of birds are, in most instances, hatched by the warmth of the mother, who sits for a certain time covering them with her wings and downy breast. But the exception to the rule in insects is that the mother has anything to do with rearing her young brood; the cases in which this takes place will be noticed in our next chapter. Generally speaking, the eggs of insects are hatched by the increasing temperature of the air in spring. The following sketch, extracted from Mr. Darwin's interesting Journal of the Voyage of the Beagle, sets before us, in a very pleasing manner, the awakening influence of this season to all nature:—"When we first arrived at Bahia Blanca, September 7th, 1832, we thought nature had granted scarcely a living creature to this dry and sandy country. By digging, however, in the ground, several insects, large spiders, and lizards, were found, in a half-torpid state. On the 15th a few animals began to appear, and, by the 18th, (three days from the equinox,) everything announced the commencement of spring; the plains were ornamented by the flowers of a pink wood-sorrel, wild peas, œnotheræ, and geraniums; and the birds began to lay their eggs. Numerous beetles were crawling about, while the saurian tribe, the constant inhabitants of a sandy soil, darted in every direction."
As to the torpid animal and buried seed, so to the carefully laid up egg, the returning warmth of the air is the signal for the commencement of life. The winter-clouds roll reluctantly back, as the genial days of spring advance, and the changes which are to have their accomplishment in the production of a living being out of the minute object before us, are set in movement as the days grow bright and pleasant. That the hatching of the egg, in most cases, is due chiefly to the stimulating influence of heat, is now well ascertained. The school-boy who has ever amused himself with silk-worms can well assure us of this fact, for he is in the habit of hatching the insect's eggs by carefully wrapping them in paper, and keeping them in his waistcoat-pocket, where they have all the comfort and warmth of his body to bring them forward. In countries where the silk-worm is reared, women carry them in their bosom, and by this means cause the young larva to come forth from the egg in much less time than it would naturally occupy. By removing a twig of a plant upon which in the preceding autumn an insect may have been found to have deposited its eggs, into a warm room, an opportunity will be had of putting this operation practically to the test. In a short time it will be found that the eggs are all hatched, and that a number of minute larvæ are crawling actively about, while their brethren in the snow-covered fields are yet safely asleep in the shell.
On the other hand, eggs which would otherwise be hatched the same year are arrested by the advancing cold of the winter season, and are now compelled to wait until the ensuing spring, before their time of hatching arrives. Evidently, therefore, to the commencement of the life of an insect the condition of the external temperature is an all-important consideration. Before proceeding immediately to consider the nature of the changes, it may be mentioned as an interesting fact, that although the eggs of insects are very quickly sensible of a slight increase of heat, and in consequence of its application to them very soon begin to live, yet they will endure the most severe degrees of cold almost without injury. As an illustration of this point we may transcribe a few sentences from a paper by the great Spallanzani upon this subject:—
"The year 1709, when the thermometer fell to 1° Fahrenheit," or thirty-one degrees below freezing point, "is celebrated for its rigour and its fatal effects on plants and animals. 'Who can believe,' exclaims Boerhaave, 'that the severity of this winter did not destroy the eggs of insects, especially those exposed to its influence in the open fields, on the naked earth, or on the branches of trees? Yet, when the spring had tempered the air, these eggs produced as they usually did after the mildest winters.'" He adds further on, "I have exposed eggs to a more rigorous trial than the winter of 1709—those of several insects, and among others the silk-worm, moth, and elm-butterfly, were enclosed in a glass vessel, and buried five hours in a mixture of ice and rock-salt, the thermometer falling 6° below zero. In the middle of the following spring, however, caterpillars came from all the eggs, and at the same time as from those which had suffered no cold. In the following year, I submitted them to an experiment still more hazardous. A mixture of ice and rock-salt, with the burning spirit of nitre, reduced the thermometer 22° below zero, that is, 23° lower than the cold of 1709, or 52° lower than the point at which water freezes. They were not injured, as I had evident proof—by their being hatched."
When it is known that many seeds will not endure these degrees of cold without injury, and those even of some tolerably hardy plants, it is the more surprising to find such apparently delicate and readily damaged objects as the eggs of these members of the insect tribe thus resisting an intensity of cold to which, in a state of nature, they are scarcely ever exposed. It is impossible to assign any rational explanation of these singular facts. It is undoubtedly owing to this power of resisting the generally deadly influence of extreme cold that we find insects reappear in spring, even in countries where the winter is much prolonged, and is of extreme severity. Thus, in Lapland we should have probably thought that the rigour of the climate would have been fatal to all insects in winter, in any condition, whether in the egg, or in other forms; but, as the poor inhabitants know to their cost, it is far different. The mosquitoes swarm in that country in numbers so prodigious that they have been compared to a fall of snow, or to the dust of the earth. The wretched natives cannot take a mouthful of food, or lie down to sleep in their cabins, unless they are fumigated to a degree almost dangerous to life. They fill the mouth and nostrils, and, minute though they are, render existence almost a burden by their blood-thirsty propensities. Not even thick plasters of the most offensive compounds,—tar, oil, and grease, are sufficient to shield the Laplander's skin from their attacks. The great John Hunter considered that this power of resisting cold was, in some unexplained manner, connected with the existence of a living principle in the egg, which had the effect of withstanding a degree of cold that would otherwise have been fatal to it; but, after all, this is only an apology for an explanation. When we are unable to clear up the difficulties of a natural history question like this, although we cannot explain, we are not prohibited from admiring, and can clearly perceive, that in thus endowing the eggs of insects with a self-preservative power, God has manifested his wisdom and forethought; for had it been otherwise, the lapse of a few seasons would have depopulated the insect world, leaving us, it is true, without a gnat or a mosquito to annoy us, but also without a silk-worm, or a bee, to supply us with the precious products of insect industry.
The frosts have disappeared, the air brightens, the sun loses its pale aspect, and glows with a more golden face. The days lengthen, the breeze has lost its penetrating chilliness, gentle showers descend and water the earth, and there is a general voice heard all over creation,—"Spring has come!" The eggs of a thousand insect species have already perceived its presence, and the newly-awakened beings within hasten to welcome it by bursting from the shell, their long occupied, but now for ever forsaken dwelling-place. Sometimes the young larva bursts through the thin walls of the shell by main force, or eats its way through by means of its jaws, which is occasionally a task of many hours' duration. "In many instances, however," write Messrs. Kirby and Spence, "the larva is spared this trouble, one end of the egg being furnished with a little lid, or trap-door, which it has but to force up, and it can then emerge at pleasure. Such lids are to be found in the eggs of several butterflies and moths. The eggs of a species of bug, besides a convex lid, are furnished with a very curious machine, as it would seem, for throwing it off. This machine is dark brown, of a horny substance, and of the shape of a crossbow; the bow-part being attached to the lid, or pushing against it, and the handle, by means of a membrane, to the upper end of the side of the egg."
But if, in our account of the various attendants on the opening of spring, we had mentioned every circumstance that takes place at that time, alas! for any poor insects, or, at least, for a large number of them, who should be hatched at that time. The warm air and gentle shower, and brighter sky, would ill satisfy them in the absence of all food, and they would be born, by a cruel destiny, only to starve and die. We well know this is not the case; but there are, probably, few persons who have ever thought much upon the admirable arrangement by which the occurrence of such a calamity to many of the insect tribes is avoided. We need scarcely remind the reader that in the opening sentence of the last paragraph there is one most important omission in the sketch of the phenomena of returning spring; that is, that there is no mention of what takes place in plants,—of the putting forth of their young and tender leaves. Now, as a majority of insects in the larva state are vegetable-feeders, we can easily understand that the unfortunate little beings if hatched before the appearance of leaves would, without doubt, quickly perish for lack of proper food. Yet the returning warmth of the air is all that is requisite to call the insect into existence, and if by the time it is ready to burst from the shell there is not food all prepared for it, it must die. The difficulty has been beautifully provided for; and perhaps, few other instances of the wisdom of the Creator in forming the insect world are so full of instructive thought as this. It has been ordained, then, that soon as winter is over, the plant is first to obey the voice of spring, and to awake; and the bursting buds on its lower boughs are already full charged with sap long before the young insect being that is to be fed therewith has left the shelter of the egg.
One of the talented authors of the Introduction to Entomology relates a pleasing anecdote in reference to this simple, yet admirable arrangement, and mutual adjustment of these two events,—the awakening of life in the plant and in the insect. "On the 20th of February, 1816, observing the twigs of the birches in the Hull Botanic Garden to be thickly set, especially about the buds, with minute oval black eggs of some insect with which I was unacquainted, I brought home a small branch, and set it in my study, in which is a fire daily, to watch their exclusion. On the 28th of March I observed that a numerous brood of aphides had been hatched from them, and that two or three of the lower buds had expanded into leaves, upon the sap of which they were greedily feasting. This was full a month before either a leaf of the birch appeared, or the egg of an aphis was disclosed in the open air." Thus showing that the coming to life of the branch and of the insects resting on it, was beautifully arranged to take place each at the proper time.
It is very singular to add, that as some trees acquire their leaves earlier or later than others, the eggs of insects which are deposited on them, never are hatched before the leaves appear, even while some of their companion eggs of a different species, and placed, therefore, on different trees, may have long since sent their young into the world. Thus, we learn that not only has God been pleased to arrange generally the hatching of the eggs of insects, and the putting forth of the leaves of trees, so that the latter shall precede the former, but it has also been ordered that the eggs deposited on each particular plant shall be hatched just when the time of that plant's putting forth its leaves shall arrive, at whatever period that may be. This may be more readily comprehended by an example: thus, there is no difference, so far as we can perceive, between the eggs of the little insects just mentioned as feasting on the leaves of the birch, and those whose food is the leaf of the ash; yet the birch will be in leaf nearly a month before the ash-tree, and the eggs deposited on it will therefore be hatched a month before those placed upon the ash, although both trees are in the same position with regard to warmth, and may even, perhaps, be within a yard or two of one another. What a beautiful and mysterious link is this, between events so disproportionately important as the clothing of a great tree with its leafy garments and the coming to life of a little throng of beings, whose dwelling-place is a small twig, and whose world a green leaf! Yet it was not too insignificant a matter for Him to arrange whose dwelling-place is eternity, and who takes up the islands as a very little thing. Does God take thought for these, and will He not much more care for and arrange well every event in the lives of his faithful children? Surely, yes.
Speaking generally, the time taken up in hatching the eggs of insects is very variable. It is a general rule that the eggs which are laid in the autumn must abide the return of spring before they will be hatched. But when eggs are deposited in the summer, they are often hatched in a very short time. The eggs of the painted-lady butterfly are hatched in about eight days, those of the lady-bird in a little less, from five to six days; the eggs of another species of butterfly occupy a month, those of spiders three weeks, those of bees only three days, and those of the meat-fly shorter than any—only a few hours; it has even been stated that in very warm weather the eggs of the meat-fly will be hatched in about two hours! In most of these cases much depends upon the weather; but even this does not operate beyond certain limits, for it has been said that in the month of June, even if silk-worm's eggs were placed in an ice-house, they would be hatched in spite of the cold, but this observation deserves to be repeated.
It would be impossible to make the exact nature of the changes which take place in the egg from first to last easily understood in a work of this kind. They have occupied the laborious investigation of talented observers with the highest powers of the microscope, and although much is now known on the subject, it is of a nature too abstruse to be dwelt upon in our unpretending volume. As we may well imagine, the changes are wonderful indeed which from a little drop of fluid matter, contained perhaps in a shell not larger than a pin's head, end in the development of the living and active larva, who makes his speedy escape out of his shell-cradle. But they must be studied in the scientific treatises which are written upon this subject, and they are so interesting as amply to repay the task of investigation. It may be added, however, as a curious fact, that contrary to the general rule in the egg of birds, some of the eggs of insects actually grow larger before they are hatched, and frequently the shape alters also.
In our account of the nests made by insects for their eggs, the examples quoted, although they furnished us with many proofs of a mother's care and forethought on the part of the insect, yet there was no instance given of anything like the solicitude displayed by the hen over her eggs. Are there then no anxious mothers concerned in the well-being of their eggs among insects also? In the next chapter some instances of a mother's care over the young larvæ will be given; and before we conclude the present, mention may be made of some interesting observations upon this subject made by the eminent naturalist M. Bonnet. The insect upon which his observations were made was the spider, so commonly found on turning up a log of wood in the fields, or a clod of earth. She carries her eggs about with her in a little round white pouch of silk attached to her body. Well has it been said, "Never miser clung to his treasure with more tenacious solicitude than this spider to her bag. Though apparently a considerable incumbrance, she carries it with her everywhere." M. Bonnet found that he could not beat away the affectionate creature from her treasure, and on forcibly removing it from her she instantly lost her ferocious aspect and became tame. In this emergency she stops to look around her, and begins to walk at a slow pace, and searches diligently on every side for her lost eggs, nor will she fly if threatened by the bystander. If, however, out of compassion, the bag is restored to her, she darts forward, catches it up with all the intensity of a mother's love, and runs away with it as fast as possible to some secret place where she may again have the opportunity of attaching it to her body. In order to put this insect's affection for her eggs to a test, M. Bonnet threw a spider with her bag into the den of a ferocious insect, called an ant-lion, who lurks at the bottom, like the Giant in the "Pilgrim's Progress," waiting for poor insect-travellers to drop into the pit which it forms, and then, rushing out, devours them. "The spider endeavoured to escape, and was eagerly remounting the side of the pit, when I again tumbled her to the bottom, and the ant-lion, more nimble than the first time, seized the bag of eggs with his jaws, and attempted to drag it under the sand. The spider, on the other hand, made the most strenuous efforts to keep her hold, and struggled hard to defeat the aim of the concealed depredator; but the gum which fastened her bag not being calculated to withstand such violence, at length gave way, and the ant-lion was about to carry off the prize in triumph. The spider, however, instantly regained it with her jaws, and redoubled her efforts to snatch the bag from the enemy; but her efforts were vain, for the ant-lion being the stronger, succeeded in dragging it under the sand. The unfortunate mother, now robbed of her eggs, might at least have saved her own life, as she could easily have escaped out of the pitfall; but wonderful to tell, she chose rather to be buried alive along with her eggs. As the sand concealed from my view what was passing below, I laid hold of the spider, leaving the bag in the power of the ant-lion. But the affectionate mother, deprived of her bag, would not quit the spot where she had lost it, though I repeatedly pushed her with a twig. Life itself seemed to have become a burden to her since all her hopes and pleasures were gone for ever."
As this spider may be easily found in the localities we have mentioned, it may interest some of our readers to make trial of the mother's care for her eggs; but, let us hope, only in a gentle spirit. Never let us be guilty of the cruelty above narrated, and leave the disconsolate mother, after her hard struggle for her treasure, without restoring it back to her. Even in an insect, a mother's love, so faithful, self-devoted, and constant, is a sacred thing; and while, as an illustration of the care it has pleased the Creator to implant in it for its offspring, it may be lawful to put it to the trial, it is wrong and cruel to do more. Never let us, for our own amusement, give even to an insect that depth of anguish and despair so beautifully expressed in the words of Jacob, as translated in the margin of our Bibles: "And I, as I am bereaved of my children,—I am bereaved."
"In order to prove," says the author of Insect Architecture, "whether a spider of this species could distinguish her own egg-bag from that of a stranger, we interchanged the bags of two individuals which we had put under inverted wine-glasses; but both manifested great uneasiness, and would not touch the strange bags. We then introduced one of the mothers into the glass containing her own eggs and the other spider; but even then she did not take to them, which we attributed to the presence of the other, as all spiders nourish mutual enmity. Upon removing the stranger, however, she showed the same indifference to her eggs as before, and we concluded that, after having lost sight of them for a short time, she was no longer able to recognise them."
The common earwig, a name at which some, who little know the beautiful traits in her character, are apt to shudder, still more closely resembles the affection of a higher animal than does the spider just mentioned. The following most interesting notice of her proceedings was published by a writer[B] in the Penny Magazine some time since. He says: "About the end of March I found an earwig brooding over her eggs in a small cell scooped out in a garden border; and in order to observe her proceedings, I removed the eggs into my study, placing them upon fresh earth under a bell glass. The careful mother soon scooped out a fresh cell, and collected the scattered eggs with great care to the little nest, placing herself over them—not so much, as it afterwards appeared, to keep them warm, as to prevent the too rapid evaporation of their moisture. When the earth began to dry up, she dug the cell gradually deeper, till at length she got almost out of view; and whenever the interior became too dry, she withdrew the eggs from the cell altogether, and placed them round the rim of the glass, where some of the evaporated moisture had condensed. Upon observing this, I dropped some water into the abandoned cell, and the mother soon afterwards replaced her eggs there. When the water which had been dropped had nearly evaporated, I moistened the outside of the earth opposite the bottom of the cell, and the mother, perceiving this, actually dug a gallery right through to the spot where she found the best supply of moisture. Having neglected to moisten the earth for some days, it again became dry, and there was none even round the rim of the glass as before. Under these circumstances, the mother earwig found a little remaining moisture quite under the clod of earth, upon the board of the mantel-piece, and thither she forthwith carried her eggs. The subsequent proceedings were not less interesting; for though I carefully moistened the earth every day, she regularly changed the situation of the eggs morning and evening, placing them in the original cell at night, and on the board under the clod during the day, as if she understood the evaporation to be so great when the sun was up, that her eggs might be left dry before night. I regret to add, that during my absence the glass had been removed and the mother escaped, having carried away all her eggs but one or two, which soon shrivelled up."
Our diligent little exemplars, the ants, are equally careful about their eggs. So soon as they are produced, the ants catch them up and convey them to a separate chamber, moistening them with their tongues, and incessantly turning them backwards and forwards. They are the objects of constant solicitude until they are hatched; they are carried hither and thither according as the temperature of the nest varies. On a sunny morning they are brought out and laid to bask in the warm air; but if the sky becomes overcast, and heavy clouds threaten rain, the careful nurses whip up the eggs and hasten with them down to the deepest recesses of the nest. They even appear to imitate the brooding of the hen, and sit upon the eggs to impart to them some of the warmth of their own bodies.
Before concluding this chapter, and entering upon the more striking manifestation of life in the form of the insect which will next come under our observation, it will be useful just to allude to the comparative number of eggs which some insects produce, which we shall place in the form of a table:—
| The Noon-day Fly | 2 |
| The Flea | 12 |
| May Flies | 100 |
| Silk-worm Moth | 500 |
| Other Moths | 1000 to 1600 |
| Wasps | 40,000 |
| Bees | 50,000 |
The most enormous number of all is produced by the queen of the white warrior ants. She deposits sixty eggs every minute, which is at the rate of 31,557,600 eggs in the course of a year, if we allow that she goes on laying at the same rate constantly, which is, perhaps, scarcely correct.
Were all the eggs produced by insects to be hatched and to bring forth living progeny, we may well ask what would become of mankind? Unquestionably in a short time their numbers would multiply so excessively as to sweep every green thing off the face of the earth, and man and beast would experience all the horrors of famine. But they are the sport of a thousand accidents, which destroy them and keep down the threatened excess of population in this world of busy creatures. And when the young larva has been put forth, this check upon their tendency to over multiplication is still more prominently displayed, as we may presently have occasion to remark.
FEROCIOUS LARVÆ OF DRAGON-FLY.
[Page 120].
THE YOUNG LARVA.
The generality of insects, as has been before mentioned, are destined never to behold the birth of their progeny, nor to experience either the pleasures or the cares of parents surrounded by their families. Their anxieties cease when they have carefully stored up their eggs, and their existence is generally soon afterwards at an end. The insect world, therefore, presents us with but few opportunities of witnessing the display of a parental affection on the part of its members; but, as was mentioned in the conclusion of the last chapter, a few examples of the kind do exist, and, perhaps, the very fact of their being few in number contributes to make them the more interesting to us. We have seen a noble instance of self-devotion on the part of a poor spider in defence of her eggs. Let us now turn to some examples of the love of an insect mother for her young larva. If the reader will carefully search the twigs and leaves of the birch-tree in the month of July he may possibly succeed in finding the little insect, the field-bug, of which mention is about being made, and witness for himself the strange spectacle described in the following account from the great work on insects by De Geer. In order that it may be recognised, we have here adjoined a representation of the insect. Its colour is a greenish gray on the back, dotted all over with very minute black spots; the under portion of the insect is greenish yellow, with black spots. It lives upon the sap of the birch-tree.
The Field-bug.
"The mother," says De Geer, "was accompanied by a troop of little ones, sometimes as many as forty in number. She remained constantly with them, generally on a twig or leaf. I noticed that the little ones and their mother did not always remain in the same place, and that as soon as the mother began to move to another position, all the little ones began to run after her, and stopped whenever the mother halted. She used to take them, as it were, for a walk from twig to twig, or from one leaf to another, parading up and down the branches of the tree, and she conducted them wherever she pleased, just as a hen does her chickens. It frequently afforded me great pleasure to observe their movements. One day I cut a young branch of the birch-tree inhabited by such an insect family, and I immediately saw the mother, apparently in great anxiety, begin to flap her wings violently, but without attempting to fly away, as though she would frighten away her enemy. At another time she would have immediately made her escape, thus plainly showing that she remained only in order to defend her young brood."
As if to furnish an instance of precisely the opposite import, the cruel and murderous father of this interesting little family is one of the greatest enemies the poor mother has to contend against. This hard-hearted parent does not hesitate whenever he falls in with one of his children to seize him and eat him up! If the mother spies him at this horrible feast she immediately attacks him in the manner described; and does her utmost to deter him from his cannibal propensities, by placing herself in an attitude of determined resistance before him. Was ever mother's love more plainly manifested than this love? No other instance of an affection so strange and strong is to be found in the tribe to which she belongs.
The care of the earwig not only extends to her eggs, but also to her young larvæ. "In the beginning of June," writes the author last quoted, "I found under a stone a female earwig, surrounded by a number of little creatures which I discovered to be her tiny family. She did not attempt to leave them, and they frequently ran and crouched under her, just as chickens under the wing of a hen. I took them up and placed them under a sand-glass, under which I had put a little fresh earth. They did not bore into the earth; and it was most curious to see them running for shelter under the mother, and pushing about between her feet, while she remained perfectly quiet. I fed them with pieces of ripe apple, which the mother seized and ate with great avidity, detaching morsels of it by means of her teeth, and swallowing them. The young ones also ate a little of it, but with less avidity."
When the eggs of the spider mentioned in the last chapter as so devotedly attached to its treasure as to prefer death to parting with them, are hatched, they make their way out of the bag by an opening in it, being assisted by the mother in this difficult task. De Geer indeed states that this is the reason why the mother clings so tenaciously to the bag of eggs, as if she knew that her assistance in extricating her young from it was necessary. But this is not altogether correct, as they are able to make their way out by themselves in due time. When the young larvæ have come forth from the shell they run towards the mother, and climb upon her body; some get on her head, some on her back, and some on her limbs. In this manner she carries them about, and is said to feed them until they become strong enough to shift for themselves. "I have more than once been gratified," (writes one of the authors of the Introduction to Entomology,) "by a sight of this interesting spectacle; and when I nearly touched the mother, thus covered by hundreds of progeny, it was most amusing to see them all leap from her back, and run away in all directions."
For another instance of affection almost maternal for the young and helpless larvæ, let us take a peep into an ant's nest. So soon as ever the young larvæ emerge from the eggs they require the unremitting attention of the best and most careful nurses in order to rear them. They must be kept clean, fed, and taken for an airing as regularly as the day returns. By means of their tongues, which are incessantly used in licking them, their coats are kept of the most snowy white. They are fed three or four times a day by their nurses, who take care to masticate the food for them, and thus prepare it for their tender mouths. But the most strange part is their regularly being taken out for the benefit of the air and warmth. Some of the ants at the top of the nest watch for the first beams of the welcome sun, and, as soon as they pour upon the nest, they hasten down below in a great bustle to wake up the nurses, and bid them take the young ones out of their chambers and bring them up to the light, which these indefatigable ants quickly set about to do. After basking there all day long the nurses take care not to expose the delicate constitutions of the larvæ to the chill evening air; and soon as the sun begins to sink towards the horizon they carefully take them up and carry them to the warm deep cell below. For fear, perhaps, of their taking cold, they never allow them to be taken out in raw, damp, or frosty weather. It must not be forgotten, however, that these ants are not the parents of the larvæ; they are only the nurses.
But it becomes us now to pursue the more immediate subject of these remarks, and ask the reader's attention to a few particulars about the larva. It is a great pity, for the sake of a clear perception of the facts of insect history, that there is a sad confusion of names in use among the majority of persons in speaking of the different forms and changes of insects. Who would imagine that caterpillar, grub, maggot, and larva, signified one and the same stage of the life of an insect? This abuse of terms cannot but render the knowledge of any science less easily retained than it would otherwise be, for the question is continually arising in the mind—If these all mean the same, why is not one term enough to express them? Let us then renounce those of uncertain meaning, and when we wish to give a name to the insect just emerged from its eggshell, let us call it by its proper name, the Larva.[C]
The larva, then, is the first form assumed by the insect on quitting its shell. No more a little inactive object lies before us, as in the egg and its slumbering tenant, but a sharp fellow, full of life, and soon walking off the field of the microscope, should we happen to be looking at it in that way, or from our book or table, should it be there placed by us for observation. By what hidden and mysterious power this has been effected who can tell? It was not heat alone that could animate the contents of the shell, nor could all a mother's care do more than preserve it from injury. It is very possible that chemistry had some share in it, and when the tiny being first awoke in the shell the oxygen of the air undoubtedly was necessary to its health, and the fulfilment of its early functions, but no more. Not chemistry, nor electricity, nor heat, nor any other known force could effect this wonderful change of apparently inanimate fluid into a lively, active, and well-organized being; much less could either of these give it its definite form, causing one larva to differ from another in its characters. No, we cannot tell how it has taken place, nor what has wrought the change; but we know the author of it—even Him who from the beginning created all things, and established those principles which, though hidden from our eyes, work out the marvels of the created world. It is enough for us to know and to remember this. Should we attempt more, we should probably fall under the Scripture reproof, "Professing themselves to be wise, they became fools."
Speaking generally, insects in the larva form appear as fleshy worms, having long and round bodies, marked with rings, and provided with a head and a certain number of legs, mostly six. How different in this condition, from the ballroom gaiety of the butterfly, or the elegant robes of the lace-wing flies. To look at a number of larvæ, all crawling over one another, and bearing perhaps not the most loving behaviour to each other as they scramble about, who would dream that, in a little while, those slowly moving bodies will be whirled through the air faster than our feet can pursue, or even than the eye can follow? Who also, but one well versed in the knowledge of insects, could venture to say what insect could be formed by this or that larva, now so little resembling winged insects at all?
Larvæ unlike the future Insects.
Larvæ like the future Insects.
In studying the forms and appearances of various larvæ, we shall find that some of them bear a tolerably close resemblance to the future insect; while others, on the contrary, do not resemble their future condition at all; and had we to decide to what tribe of insects they belonged, merely judging by their shape and character, we should be sorely perplexed to do so, and if we did, we should often in all probability be very far wrong. We need not go far for an illustration, first, of a larva like the perfect insect, and next, for one totally unlike it. Taking a candle and exploring into some snug hole near the kitchen fire-place, we shall not be long, probably, before we extricate a number of the larvæ of the cricket. Those of the bug also are very like the perfect insect; so also are young spiders, cockroaches and grasshoppers. These all resemble more or less perfectly the insect in its complete form.
Even amongst the larvæ not resembling the perfect insect, a little attention will enable us to perceive a sort of general resemblance between those of different genera and species, which we may call the Larva family likeness. This consists in the form of the body, in a number of instances; but in all in the ring-like marks or segments of the body, as they are called, which are thirteen in number. If the reader will take the trouble to count the rings in the larvæ of different insects, he will generally find that they are thirteen in number. The general resemblance of larvæ to one another may also be noticed. The larva is, in every instance, destitute of wings. In many cases, larvæ are provided with feet, in many others they have none. And in some instances, they have no distinct head, as in the larva of the blow fly.
By far the larger number of larvæ belong to this class; that is, they do not resemble the perfect insect. Do not resemble! could any one believe that these strange, and some of them awful looking larvæ ever became butterflies? yet they all belong to that tribe of insects.
In order to give a clear conception of the structure of a larva, we may briefly mention the names of its various parts. First then, there is a head of various shapes, sometimes of the shape of a heart, sometimes round or triangular. Attached to the head are the two antennæ; or, as they are commonly called, feelers, most probably an incorrect expression, as it appears that insects may possibly hear as well as feel by their means. At the side of the head are the eyes, which are formed much more simply than those of the perfect insect. Next is the mouth, provided with its upper and lower pair of jaws. Then there is the body and its legs; and lastly, there is in many larvæ, living in the water, a tail, which, strange to say, is provided with a delicate tube, through which the larva breathes. A beautiful instance of such an appendage to the body of the larva, is represented in the adjoining cut; the various parts of the larva are also represented in the accompanying figure.
Diagram of a Larva.
We may now enter upon a few particulars connected with the general history of insects in the larva form.
HABITS OF THE LARVA.
Generally, for a little while after the larva has emerged from the shell, it is in a very weak and languid condition. The effort of extricating itself from its little prison-house, seems to leave it almost without strength; and for a period which varies in different insects, it lies helpless and almost motionless at the mercy of any wandering adversary, and might be demolished without resistance. But this hour of weakness, except in a few cases, is not prolonged. In the course of an hour or two, or even much less in some instances, the larva revives, takes heart, and begins by eating whatever food may happen to lie in its way; and now the larva becomes a terror to the world of insects, or even, indirectly, to man and to nations. Instead of simply eating, in order to live, like most other beings, it only lives to eat; it has no other duty to perform at present but to eat as fast and as much as it possibly can in a certain time; and it must be confessed, the larva, generally speaking, leaves little to be desired on the score of a sharp appetite. Unlike other creatures who allow themselves a certain period between their meals, the larva sets to its feast and does not leave the table until it has devoured all its contents,—upon which it immediately begins again elsewhere. No gourmand in the world, whether among human beings or brutes, can compare with the insect in this form for the amount of food consumed. Morning, noon, and night, is to it only a continued round of feasting; and, as may well be imagined, the larva grows very rapidly accordingly. Some larvæ consume animal, others vegetable food; or, in the language of science, some are carnivorous, some are graminivorous or herbivorous, and some will eat anything almost that comes before them—these would be called, and very appropriately so, omnivorous.
Let us speak of carnivorous larvæ first. The larvæ which have carnivorous propensities render themselves often truly terrible to the insect world around them. The most mighty warrior that ever lived in his whole career never slew half so many of his own species as the larva of a beautiful fly does of aphides in a few hours. Well does Réaumur call them the "lions of the aphides," and thus does he describe their method of proceeding:—
Lion of the Aphides.
"There is no beast of prey in nature who hunts so entirely at his ease as does this larva. Resting upon a twig or a leaf, he is surrounded on every side by the insects on which he feeds; often, indeed, they touch his sides, and he is able to catch hundreds of them without changing his position. Not only do the poor little aphides not fly from him, but they may be often seen creeping over the body of their enemy. It is only after the larva has eaten up the greater number of his prey around him, that he has any need to remove to a spot as thickly inhabited by them as that in which he has been making his cruel ravages. In order to observe the manner in which he attacks them, the best plan is to take him, put him between two leaves, and shut him up in a box for ten or twelve hours to sharpen his appetite. After this fast he must be placed on some spot where the aphides are found in abundance. Immediately he begins exploring around for prey, which he does simply by the sense of touch, as he does not appear to be able to see. At length an unhappy insect comes within his reach. Brandishing a trident with which he is armed, he immediately transfixes the insect, just as we take up a morsel of food upon a fork!" The little creature is then sucked into a sort of cavity like the neck of a bottle, where it is retained by a couple of pins until its juices are emptied by the destroyer, when he casts it away, now nothing more of it being left but a dry, shrivelled, empty skin. The aphis-lion, however, loses no time, and presently seizes another, which he pierces and sucks dry as quickly as the last.[D] When very hungry he will devour one a minute. Réaumur says, "I have seen him eat twenty of these insects one after another in twenty minutes; nor did this satisfy him: for in the course of two hours he devoured more than a hundred insects with which I supplied him!" These larvæ do repose a little, but never for long, for they are seldom without some prey in hand. "I have seen," adds the last author, "twigs of the elder seven or eight inches in length entirely covered with these insects, (the aphides,) and in four days' time there remained not one alive."
This larva is a rare specimen of courage, as well as of destructive powers; for when it is quite young it often seizes upon an insect twice as big as itself. It is very amusing to see the unequal contest between the little but courageous foe, and his great, bulky, and stupid adversary. Immediately the larva thrusts its trident into the body of the enemy, who, stupid as he is, does not like the sensation of the wound in his side, and makes off as fast as he can. The lion-hearted larva follows him up and wrestles with him, and at length actually boards him, to use a sailor's term, clambering up his sides, and, in triumph, piercing him through and slaying him. What is perhaps most singular of all, the larvæ of some species of these flies not only slay their victims, but actually clothe themselves, after the manner of Hercules on his victory over the Nemæan lion, with the skins of their prey!
It is almost to be regretted that the insect world has not had the privilege of having its combats sung by the poets. Who can forget the animated scenes, painted in such life-like colours by Homer and Virgil, of the conflicts, hand to hand, of the heroes of their verse? But the history of insects supplies us with more singular and more interesting deeds of fight than have ever yet been fabled by poets, or commemorated in song. In the instance we are about to quote, the larva of the ant-lion is the crafty Giant Grim, who lives by entrapping, as we have before said, poor wayfaring travellers. Like those giants of old, of whom we read in books a little more wonderful than true, this subtle and powerful enemy lies deeply ensconced in his subterraneous cavern, patiently abiding the time when his unsuspecting prey shall fall into his power. His trap is depicted on the opposite page.
An Ant-lion in its Trap.
This insect is naturally a very helpless being, it can only walk at a slow pace, and strange to add, it can only walk backwards, and not forwards! Yet its food is the juice of insect bodies. How, then, is it to seize upon them circumstanced so unfavourably as it is, having neither swiftness nor ability to direct its motions sufficiently actively to fit it for such a task? It succeeds by an artifice of the most refined character. Nothing daunted by what we might call its natural disadvantages, the insect sets bravely to work to construct a trap for its prey; and the manner in which this is performed may well strike us with wonder, and raise our admiration up to Him who has so marvellously endowed this humble being with wisdom and skill. It first takes care to choose out a proper site for the work it is about, and in this always selects a soil composed of fine, loose, and dry sand, well aware that, as we shall presently see, no other would be fit for its purpose. Generally it chooses such a soil under the shelter of an old wall, where the rain cannot easily penetrate and ruin its work. In so doing it shows its wisdom; for thither, when the heat of the sun is great, or when the rain-drops fall heavily, crowds of insects come for shelter, and fall into its cruel embrace.
Circular Ditch of the Ant-lion.
The site being chosen, the next important step is to mark out the bounds of its habitation, and with this view the insect begins digging a circular ditch, walking backwards until it has completed the circle. This defines the outer limits of its trap, and is a sort of guide line to it in its future operations. Then it sets about the more proper task of excavating its trap. Would that our readers could see this insect at work! Of all the wonderful sights presented to us in the insect world there is none to equal it in interest, none so calculated to enlist our sympathies on the part of the patient, skilful, and unwearied little labourers of this kingdom of nature. Guided by the line it has marked out, the workman steps into the circle, and sets to work with a hearty good will, and with a degree of diligence and excavating skill that would put our railroad "navigators" to the blush. Shower after shower of sand is seen flying up and beyond the boundary described, with the most unintermitting diligence, until the insect has completed the circle again; arrived there, it turns round and excavates back again until it arrives at the same point. But it may perhaps be asked, where are its tools, and by what means does it succeed in casting up these loads of earth? We fear that at best any written description will hardly do justice to our ingenious labourer; its method, however, is as follows:—It uses the head as the spade, or rather shovel, and in the strangest manner it fills the shovel with one of its feet with a load of sand, and then by a quick movement of the head tosses it out of the cavity. By working in alternate directions it manages so as never to over-fatigue one leg, for on its return the leg previously in use is at rest, while the one on the opposite side is now called into duty. The insect thus works on until its trap is completely excavated, the task occupying a variable time; sometimes being finished in half an hour, sometimes even in less, but occasionally occupying several hours, the little labourer being obliged to rest a certain time. Réaumur, who has given a fascinating account of these insects, writes, "I have had at times hundreds of ant-lions in a large box, and I have often been amused with filling up their traps. Some of them would immediately begin to form another; but the greater number in the warm long days of summer deferred executing the work until the sun began to go down. They seldom worked in the heat of the day; but in cold or cloudy weather they would excavate at any hour."
We well know what perplexity a chain of rocky hills causes to a railroad engineer, and what vast outlays of money, labour, and time are necessary in order to overcome the obstacle thus presented to the path of the engine and its train. But it may be safely said that we can furnish a parallel instance of difficulty and of patient, all-surmounting exertion from the history of the insect before us. M. Bonnet was curious to know what it would do if a stone or some such obstacle were met with in the process of its excavations, and one day had the gratification of observing the behaviour of the insect under these trying circumstances. Not being able to cast it out with its head, the insect determined to carry it out, if possible, on its back. With this view it contrived by various manœuvres to place the stone upon its back and to balance it there. This was the least difficult part of the undertaking. The insect had to climb up an inclined plane upon soil, chosen with other views purposely by itself, as shifting and unsteady as possible, and not only so, but to preserve the balance of the stone with which it was encumbered. Undaunted by these difficulties it made the attempt, but the first step brought down a shower of sand, and tumbled the little rock to the bottom. Again and again did the heroic insect attempt the same feat, and with the same ill success, and we might have thought we beheld a realization of the fable of Sisyphus and the rolling-stone, in the vain endeavours of the insect to get rid of its encumbrance. Five or six times did the insect repeat its endeavours, and at last, after one or two narrow escapes, the stone was fairly lodged on the outside of the trap, and the insect returned to its subterraneous recess at the bottom of the cell in triumph.
The traps vary in size in proportion to the age of the insects which construct them. The young insects only form very small ones; but as even from the moment of their birth they are destined to toil for their food, they do not wait in idleness and hunger because they cannot make large efforts, but are content to make little traps not more than a few parts of an inch in diameter. Thus they set us the needful example of not despising to do small things because our strength is not yet equal to the performance of as much as we could desire. The diameter of the trap formed by a full-grown insect is about three inches; the depth about two.
When its labours are over, it has been well remarked, the insect now only requires patience—but it must have a good deal of it! It generally buries itself, all but its jaws, in the sand at the bottom, and here awaits its victims. If it requires much patience, surely it also needs to have much power of endurance of hunger, for it may wait for days sometimes without catching any prey. Frequently, when this is the case, it marches out of its trap, and tries its fortune in some more favourable spot. But see! an ant who has been out foraging for the young ants at home is hastening back laden with sweet treasures, when suddenly she finds her path arrested by what appears to her to be a deep but smooth precipice. To plunge down and rise on the opposite side is a shorter cut, in her estimation, than to go round; or perhaps she is led by curiosity to wish to explore this singular cavity, and she plants her feet on its treacherous edge, causing a few grains of sand to roll down and give notice to the wary giant below that a victim is at hand. A step back, and her life would be saved; but no, she leaves the bank, trusts herself to the unfaithful soil of the sides of the precipice, and instantly rolls down in a cloud of dust to the bottom. Terror has now laid hold of her, and with all speed she strives to clamber up the unsteady sides. For a moment escape appears possible, but the Argus-eyed monster below starts up into activity, and piling upon his head a huge load of sand, he shoots it after the escaping ant, and once more brings her down covered with dust into his embrace. The terrible jaws are instantly closed upon the unhappy insect, and in a few minutes her existence is at an end, the savage enemy shaking her violently, or dashing her quivering frame against the earth.
Singular to add, the ant-lion loves not dead prey, and will indignantly cast it out of its trap. Says Réaumur, "They appear so much to delight in the glory of a victory, that they disdain to touch an insect who is not, to say the least, in a condition to contend with them!" It certainly is not that the food when offered to it dead is not fresh enough that it is thus treated; for if only killed an instant before the insect still refuses to touch it. Réaumur is disposed to believe that, like our sportsmen, these interesting but cruel insects destroy prey more for the pleasure of exhibiting their superior skill, than to appease their hunger. But it is rather uncharitable even to the ant-lion, to say so much as this. When the insect has sucked all the juices out of its victim's body, it casts it out of its trap, and the earth around, strewed with dead bodies, is thus the silent witness to the destroying powers of the giant within.
This singular insect, whose exploits have detained us so long, remains in its larva form two years, growing daily in size until it has completed its existence as a larva, and must then enter upon another condition of life. It is to be regretted that it is not to be found in England, or at least it has not been for some time discovered in our island; but it is common in France and other parts of the continent, and would well repay the trouble of being brought over. As the insect is very patient of hunger, it might easily be conveyed in a little wooden box, half filled with fine sand, and its proceedings could be readily watched by placing it under a bell-glass, or in a little glass case, introducing a few ants or spiders for its food from time to time.
The insect exhibits to us a wonderful instance of what we may call, after the example of Dr. Paley, the principle of compensation in nature. It can neither run nor fly with the speed necessary to overtake its prey who are swifter of foot than itself. But God never created it to starve, and has endowed it with a rare combination of faculties by which it is enabled to live in the midst of plenty if not even of luxuriance. So it is in a thousand other cases in nature. So it is indeed in Providence likewise. If He sends us trials, "He also makes a way to escape that we may be able to bear them." If our day is to be dark and cloudy, and to call for the exercise of much faith and patience, there is still the same provision made; "as thy day so shall thy strength be." If our lot in life is one of hardship He can, and if it is sought of him aright He will, and He does bear us up, revive our drooping strength, and enable us to go on our way rejoicing.
Cells of Sand-Wasp.
Let us go on to speak now of some other carnivorous larva. If in the month of July we can find out a spot where we can detect the traces of the labours of the sand-wasp, of whom mention has been made at page 15, and cutting out a little mass of the sand-rock containing several of their burrows, then take the trouble to open gently one of the cells formed by these insects, we shall see a carnivorous larva in as happy a condition as a fox in a hen-roost, or a mouse in the midst of a cheese! The best way to obtain access to this securely imbedded and luxurious larva, is to moisten the mass of sand with a little water, and then slice it gently down with an old knife until we come to the cells. They are here represented. At the bottom of each we shall see the larvæ which have sprung from the eggs deposited in the manner before described, after the arduous and affectionate labours of the parent. Then above each is a heap of caterpillars, arranged with beautiful neatness, and larvæ and caterpillars are both fast locked in their prison house by the firm stopping with which the parent wasp has closed the mouth of the cells. These caterpillars are all alive, and are rolled into a ring-like form, but are so chained down that they cannot move in the least degree. The poor prisoners, like the sheep in the slaughter-yard, are only waiting their turn to be killed and devoured. The larva soon after it is hatched finds himself in the midst of a well-stored larder, and has nothing to do but eat, which he does not long delay doing. He devours at his ease, and revels in the dainty fresh food which the care of his parent had laid up. When he has eaten all his prisoners up, and grown to his full size, he lays down to sleep, to awake again in another and a far different form.
Larva of Wood-boring Wasps.
Sometimes the reader may have the opportunity, it may be, of finding out the nest of the wood-boring wasp, and he may in June or July, perhaps, succeed in discovering another instance of a larva in a happy state of plenty. The larva is sure to be found at the bottom, and above it will be piled a heap of insects for its food. What is remarkable about this store of food is, that the insects thus made prisoners are not dead, for they would, if so, soon become corrupted, and unfit for the diet of the larva; they are in a sort of half stupified condition, in all probability very like that induced by the late plan of breathing ether and other vapours to render persons insensible to pain, while surgically operated on. Since this plan has been introduced, we read in some of the newspapers—we may question with what truth—that the butchers in Albany (America,) give ether to the oxen before killing them, so as to make them insensible to the pain of the death-blow! But the wasps in question have for ages been in the habit of effecting the same end by stinging their captives, the poison not sufficing to kill them, nor yet permitting them to be actively alive.
The insects thus stored up for the larva cost the parent many a conflict in their capture. And here we may interest the reader by describing the exploits of a warrior wasp, abundant in the Isle of France. It is curious that in the Isle of France the common bee is not to be found as a native of the woods, while, in the Isle of Bourbon, it is very common, and furnishes an abundance of wax and honey. This is explained by supposing that the warriors of whom we are about to speak destroy the bees, and have thus prevented their multiplying in the island in question. Truly, like the banditti of whom we read in books, these wasps are splendidly attired, although not in the spoils of those they have robbed. Their head, chest, and body is of a resplendent lustre; now green, or, seen in another position, blue, and glistening with all the lustre of an exquisite varnish; their antennæ are black, their eyes of a brownish yellow, and their legs partly bronze-coloured, and partly of a beautiful violet. They are strong and swift of wing, and are possessed of a terrible lance, the thrusts of which even man cannot endure without far more pain and inflammation than attends an ordinary sting.
The foe with whom these magnificently-dressed warriors have to contend, is a kind of insect allied to the cockroach, which, in our kitchens, has acquired the incorrect title of "black beetle." This insect is detested by the inhabitants of the island, for its ravages upon almost everything of value or delicacy, and is not less hated by the sailor for its destructiveness on ship-board. It is called Kakerlac, and is much larger than the cockroaches, which are the plague and terror of our cooks. Imagine that one of these great and odious insects is marching along the highway. The warrior wasp has also been making his expeditions for prey abroad, when suddenly his eager eye catches sight of the kakerlac hastening to some new scene of depredation. The warrior instantly alights, and the kakerlac stops, thinking perhaps to intimidate its adversary by its size and ferocious aspect. Both insects glare at one another;—
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——"each other from afar They view, and rushing on, begin the war. They launch their spears; then hand to hand they meet, The trembling soil resounds beneath their feet; Their bucklers clash, thick blows descend from high, And flashes of fire from their hard helmets fly. Courage conspires with chance, and both engage With equal fortune yet, and mutual rage." |
Virgil's description, though scarcely accurate in all points, gives us a lively image of this insect combat. The kakerlac, however, is the Turnus, and the warrior wasp the Æneas of the fight. The wasp is the first to attack, and darts upon the other, seizing it by the muzzle with its strong jaws, then bending its body so as to bring its tail under the abdomen of the kakerlac, the lance with its charge of poison is deep-plunged into the body of the unhappy foe, imbuing a deadly venom into its system. Having made this thrust, the warrior looses the foe, and soars in triumph a little way into the air, satisfied of a successful issue.
The wretched kakerlac, after a few brief convulsions, lies paralysed on the ground unable to stir a step from the spot where it encountered its terrible adversary. Fully aware of this, the victorious wasp, after taking a few turns, as if to proclaim the downfall of the Giant Kakerlac to the surrounding neighbourhood, returns to the scene where the conflict was fought. The kakerlac, unable to resist the victor, and being naturally, though a great devourer, a very faint-hearted creature, lies immovable while the wasp seizes the prostrate foe by the head, and in a sort of triumphal march drags it along the road to its nest. But though the kakerlac was not a difficult enemy to overcome, the weight and size of its body are a sore burden to the victor wasp. The way to the nest is long, tedious, and rugged. After a hard pull over all sorts of obstacles the wasp becomes completely breathless, and is obliged to let go, and for a rest it generally rises into the air, probably with a view of reconnoitring future difficulties, and of ascertaining the best route to pursue. Thus, after alternately dragging along the body of its victim and rising up to spy out the path, at length the conqueror succeeds in bringing the carcase home.
Here, however, arises another difficulty. To attempt to get the body of the huge kakerlac in, is just as if one were to attempt to get an elephant through a small street-door. What is to be done? The wasp enters the hole backwards, and, seizing the head of the kakerlac, endeavours with all its might to drag it in, but all in vain. Many times it repeats these efforts with the same want of success; and now it appears that its labours in bringing hither the corpse, and its dangers in the battle, were all for nought, for the great body cannot be put in the place the wasp had designed for it. As if exasperated with the difficulties, out comes the wasp in fury, and falling upon the body of the kakerlac, hews off the large wing-cases, together with several of the limbs, and goes back into the hole again to repeat the attempt to get it in. Success at length crowns its efforts; by little and little the body becomes lost to sight, and finally disappears altogether from view, being carried down to the very bottom of the nest. Here the larva, as soon as hatched, feeds upon it, thrives, and grows, and falls asleep, awaiting the time when itself shall awake to follow in the steps of the glittering and formidable warrior who, with the boldness of an amazon and affection of the tenderest of mothers, supplied it with nourishment during its hours of infancy.
This may be thought a scene of sad carnage, but the following will, perhaps, appear even more so. What should we say, if deep in the forests of some wild uncultivated country was found a den, the bottom of which was strewed with skulls, with bones, and mangled limbs? What fearful scenes should we not suspect to have taken place in this dark and horrid place; and as we shuddered in looking round upon its walls, as the once witnesses of terrible deeds, we might even fancy we heard the cry of the poor traveller, whose last agonies were seen by no eye but that of the monster who had waylaid and murdered him? Such a den may be found in the forest, made horrible by the cut-off heads, limbs, and wings of insects—it is the habitation of the carnivorous larva of a wasp. Nay more, as is seen in the engraving, the insect monster actually works up the cut-off wings and limbs into a sort of covering for itself, and finally buries itself in a shroud partly made of the spoils of former victims.
The Larva of a Wasp in its coat of wings and limbs.
Perhaps the carnivorous larva of the tiger-beetle, or cicindela, is as ferocious a being as any in this state. In this respect, indeed, it resembles the perfect insect, whose title sufficiently indicates its swiftness, cunning, and blood-thirsty nature. "These larvæ," writes Mr. Westwood, "burrow cylindric retreats in the earth, to the depth of a foot or more, employing their legs and jaws in loosening the particles of sand and earth, which they carry to the surface upon their broad, saucer-like head, ascending by the assistance of the two hooks upon the back, somewhat after the fashion of a sweep going up a chimney! Having completed this burrow, they station themselves, by means of their legs and back hooks, at its mouth, their large flattened head and great segment filling the hole." Here they remain all day long, and many an insect might pass close by, little dreaming of the terrible foe who lay under that trap-door. Presently comes a spider scrambling over the ground in haste to mount up a branch on which to hang one of its web lines; the treacherous trap-door is in its direct path. Its feet rest on it; instantly the trap drops, and the poor insect falls into the dark den, and is caught in the powerful jaws of the artful larva. Truly, there is something even to man a little intimidating in the sight of such a monster as is represented here; how much more to the unfortunate insect who happens to be caught in its embrace, and having only time to just catch a glimpse of its fearful captor, is dragged down in a cloud of dust to be devoured in darkness at the bottom of the den. Yet this also, like other cruel creatures, is in reality a very timid larva, and instantly on the approach of danger, drops to the bottom of the cell, where, if we have courage to pursue it, we shall find it much in the attitude in which it is here represented. The singular pair of hooks on its back are used as the flukes of an anchor to sustain the insect in the position it assumes at the mouth of the cell.
Larva of the Tiger-Beetle.
Mention has already been made in the previous chapter of the insects called Ichneumons, which deposit their eggs in the bodies of the larvæ of other insects. These, when hatched, are also to be reckoned among the larvæ which prey upon flesh, since they devour the bodies of the larvæ in which they have been deposited. They are thus most useful to mankind in destroying the devourers of his vegetable food.
Larva of the Dragon-fly.
The Mask partly open.
The same partly closed.
We may now see an instance yet more strange of a carnivorous larva. We must wend our way to the riverside in the months of May or June. There, after a diligent search at the bottom, in some moderately shallow portion of the stream shall we find a larva, the study of which might well occupy us for many pages. Yet it is the larva of an insect well known to every angler and brook-side wanderer—the dragon-fly. This larva is provided with one of the most remarkable contrivances for seizing its prey and conveying it to its mouth, of any being in the zoological kingdom. By the assistance of the engraving, we may perhaps be able to render this apparatus, which is somewhat complicated, intelligible to the reader. Looking at the larva's head, we are reminded somewhat of that of a horse who has got blinders over his eyes, and a nose-bag over his nose, and partly up his cheeks. Now suppose the two blinders thrown back on each side, then conceive that the lower part of the face which we have supposed covered with a nose-bag were to be uncovered, we should then see the following curious contrivance. The lower lip of this larva is lengthened downwards into a sort of arm, if we may so speak; at what we may call the elbow, is a joint connecting the upper and lower portions of it, and the place of the hand is occupied by two cross plates, with a claw at the end of each. Suppose an unhappy insect, or even a tadpole, swims carelessly by the larva, immediately the two sides of the mask, or blinders, as we have called them, fly open; the arm is uncovered, the forearm let down, and by means of the plates, which we have compared to the hand, the victim is caught, and bending the arm back, is presented to the mouth of the larva. There is much similarity in this organ with the wonderful apparatus of the elephant called its trunk; but of the two, the trunk of this insect is the most beautiful piece of animal mechanism. When the prey has been devoured, the arm folds up, covers the mouth and part of the face of the insect, and the blinders, or two side pieces of the mask, fall in, and lock together in a toothed manner, as the engraving in the last page shows.
The apparatus in the act of seizing.
Thus provided, the larva is a formidable creature to the inhabitants of the pond or brook; few, indeed, more so. It preys with incessant activity on all aquatic insects that happen to come in its way, and sometimes, as we have said, even upon tadpoles. They do not even spare one another, and woe to the unhappy relative of the family who happens to wander near the abode of another of the same family, anxious to begin his feasting for the day! So ferocious are they, that they even attack small fish, and make little work of swallowing them up. Not only are these creatures fierce, but they also possess all the cunning of a tiger or a cat. To watch them seize their prey is an interesting occupation, and as the larvæ are common enough, and may be easily recognised by comparing them with the accompanying cut, we may venture to recommend the amusement of observing their proceedings to the reader. A little way off lies an unsuspecting insect delighting in the warm sunshine, and securely floating upon the waters on the corner of a leaf. Such an idea as danger at hand is probably the very last from its conceptions, and pluming its bright and glossy wings, it beguiles away the sunny hour unmolested by a passing enemy, or a breath of air. The larva has marked it already for its own.[E] See it rouse itself up, and noiselessly make ready to pounce upon the unsuspecting lounger. It creeps stealthily along, concealing itself from view as far as possible, and not even the tell-tale glassy surface of the water feels its movements. Measuring its distance well, the larva prepares to seize its prey; in a moment, swifter than the eye can follow, the victim is caught by the apparatus we have described, and in another instant, is in all the agonies of a violent death in the mouth of the larva. So exceedingly cautious are these larvæ in their movements, and so expert and active in darting upon their prey, that it scarcely ever escapes their power.
Cockchafer.
Larva.
Having mentioned these particulars about carnivorous larvæ, let us consider some circumstances connected with those larvæ that are vegetable feeders—graminivorous or herbivorous. Of these, we could scarcely select a more destructive one than the larva of an insect well known to every school-boy from the times of Greece and Rome down to our own—the common cockchafer, (Melolontha vulgaris.) Our schoolboys, however, are less merciful than those of Greece, for they only tied a string round the leg of the unhappy cockchafer, while these thrust a pin through its tail. Yet, its terrible ravages considered, the insect little deserves to be pitied; but, we are not therefore to be understood as by any means sanctioning the cruel and inhuman sport alluded to. These larvæ are hatched in a sort of little cavern dug by the parent insect's care under the ground in our meadows, or corn-fields. Here they begin their ravages by devouring the roots of the grasses which surround them on all sides. In this manner they very quickly destroy the plants, which wither and die in a manner quite mysterious to the agriculturist, if he does not happen to think of these insects. The turf soon becomes so completely undermined by these excavators, that it may be rolled off as smooth as if a knife had been used underneath to cut off all its connexions with the ground. In a few weeks, meadows which shone in all the fresh and luxuriant green raiment of Spring, change colour, and before Summer has yet come, and before the stalks of the grass are yet grown up, one would think Autumn had passed over the face of the field, from its dry and dead aspect. About seventy years ago, we are told these larvæ did so much injury to a poor farmer's fields near Norwich, that the court of that city, out of compassion, presented him with twenty-five pounds. Some idea of their numbers on this farmer's property may be formed from the fact that the farmer and his servant declared, with very long faces, we may be sure, that they had gathered eighty bushels of them. Sometimes they even attack the roots of young trees, and in this manner do an incalculable amount of mischief to plantations. They were at one time so abundant in France, and did such immense mischief, that the Government, in order to get rid of them, offered a handsome reward for the best method of destroying them. A number of experiments were made, and it really seemed as if nothing would kill these larvæ, in the way of poison at least, for several poisons which are rapidly fatal to man and animals failed to produce the least effect on them. It was found, however, at last, that a solution of alkalies, such as potash and soda, were certain poisons to them, and should land be much infested with them, it would be worth the trial to water it with such solutions, especially as they tend rather to enrich the soil than otherwise. A French manufacturer, determining to turn the visitation of these insects to good account, has succeeded in distilling an excellent lamp-oil from their bodies, and offers tenpence a bushel for them. From seventeen bushels he extracted twenty-eight quarts of good oil! In Hungary, a kind of grease is obtained from them which is useful for carriage wheels. The ingenuity of man may thus even procure good out of a very formidable evil, although the mischief done by the cockchafer larva undoubtedly far exceeds the benefit it confers upon its captors in the amount of oil extracted from it.
An insect almost equally familiar to all persons is the long-legged gnat, of whom the famous children's rhyme runs:—
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"'Old father long-legs' would not say his prayers; Take him by the left leg and throw him down stairs." |
Many of our farmers would be glad, no doubt, if taking him by the left leg would keep him out of their meadows, for there this insect commits fearful ravages in the larva form. In some parts of England it has as completely destroyed the pasture-grass as if it had been consumed by fire. In the spring of 1813, hundreds of acres of pasture in the rich district of Sunk Island in Holderness were entirely destroyed by it, being rendered as completely brown as if they had suffered a three months' drought, and no other vegetation but that of a few thistles was left on land, which, at more favoured periods, was more than commonly luxuriant. On a square foot of the turf being dug up from the affected spot, the enormous number of two hundred and ten larvæ was counted in it. Fortunately, the next year showed a very different result, for then it was difficult on careful search to find one! In some districts of France it is also very destructive, the grass of large tracts being so completely destroyed by it, that enough food for the maintenance of the cattle is not to be obtained. These larvæ, like the last-named, appear to destroy by eating away the roots of the grass. From these and the foregoing facts, entomology teaches us to regard these two insects, upon which we commonly look with compassion, as occasionally becoming the formidable, though indirect, enemies of man. The scientific name for "Father Long-legs" is Tipula oleracea. The French call them oddly enough milliners, or tailors, (couturiéres, tailleurs,) a name of which it is harder to guess the origin than the common one of father-long-legs, which is sufficiently expressive of one of the features of the insect in the perfect state: perhaps the French tailors are distinguished for being very long and thin!
The Gamma Moth and Larva.