CHAPTER I.

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 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?

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.

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We may now enter upon a few particulars connected with the general history of insects in the larva form.