Larva

“ A survey of the multitudes of insect larvae—grubs, caterpillars, maggots—living on land, on plants, underground, in the water; feeding on leaves, in stems, on roots, on carrion, on refuse; by hunting or by lurking after prey; as parasites or as scavengers, brings home to us most strongly the conclusion that each larva is fitted to some little niche in the vast temple of life, each is specially adapted to its part in the great drama of being. ”

“ The changes are not only observable in the body and its appendages, but also in the internal organs, and consequently are both structural and physiological. The term larva, as applied to the first stage of animals, is a very variable and indefinite one, that of insects in general being a much more highly organized animal than the larva of a worm, starfish, or crustacean. ”

“ Characters from the larva and pupa.
Larva depressed, kaned; has sixteen feet, lives through one or more winters, never rolls itself in a ring when touched, feeds on the solid interior woody parts of vegetables; pupa changes in a tough cocoon, in which are interwoven particles of the larva's food; it has a double row of small raised denticulations on each segment of the abdomen, which give it partially the power of locomotion. ”

“ The painted wings of the insect in its second stage of existence are the sublimated cabbage it has devoured in its condition of larva.”
“Quite so. What has that to do with me?”
“We are also in our larva condition. But do not for a moment suppose that the wings we shall put on with rainbow painting are the produce of what we eat here—of ham and chicken, kidneys, beef, and the like. No, sir, certainly not. They are fashioned out of the information we have absorbed, the knowledge we have acquired during the first stage of life.” ”

“ I have seen a young neuter gnaw a piece out of the side of a dead wasp larva fallen from its cell, and turning, offer it as food to the mouth of the self same larva. More than this, I once observed a neuter attack a live larva and, after she had cut out and crushed a fair-sized piece of its body, come back eight times in the course of her examination of the cells of the nest to this larva, which had naturally died in the operation, and offer it this part of its own body with the evident expectation that it would be seized and eaten. ”

“ A larva, it may be explained, is the stage in insect development which follows the egg; the next stage is known as the pupa. When the eggs are first laid they are white but, before they hatch, they become darker and darker, till they are almost black. ”

“ The larva of the male must have a different instinct from the larva of the hermaphrodite; for the latter attaches itself head downwards to a coralline, whilst the male larva crawling on the scuta of the hermaphrodite, discovers, I presume by eye-sight, the fold in the shell beneath the translucent border of chitine, and there invariably attaches itself. ”

“ In Fig. 89 we represent the larva and pupa of a bee; it will be seen that the difference between the two forms is very great, while the further change that will be required to complete the perfect Insect is but slight. When the last skin of the larva of a bee or of a beetle is thrown off, it is, in fact, the imago that is revealed; the form thus displayed, though colourless and soft, is that of the perfect Insect; what remains to be done is a little shrinking of some parts and expansion of others, the development of the colour, the hardening of certain parts. ”

“ The primary larva, with its various appendages closely wrapped against its body by a common sheath, with its fish-like form and its single and only partially movable limb, is perfectly adapted to make the difficult passage to the outer air. ”

“ The details are briefly as follows:—A female fly lays a few, very large, eggs, out of each of which comes a larva, that does not go on to the perfect state, but produces in its interior young larvae that, after consuming the interior of the body of the parent larva, escape by making a hole in the skin, and thereafter subsist externally in a natural manner. ”

“ As a matter of fact many of the special organs of the adult, the legs and wings, for example, begin to develop as little buds or groups of cells in the body of the larva, and when the larva is ready to pupate these imaginal wings and legs are drawn out to the external surface of the body, and may be readily recognized as they lie on the ventral surface of the pupa folded and closely pressed to the body surface. ”

“ The larva and the adult insect have become in many cases so divergent in structure, as a result of their separate departures from the ancestral path, that the embryo bas become almost a double creature, comprising one set of cells that develop directly into the organs of the embryo and another set held in reserve to build up the adult organs at the end of the larval lit'e. ”

“ By and by it will have strong wings, long, strong legs, a horny body, and very often colors like a rainbow.
But this which you call a “white worm” is the beetle larva after it is born from the egg. Sometimes it has no eyes. It is always very greedy. Beetle larvæ will eat almost anything but metals. They harm wood, trees, fruit, flowers, meal, furs, clothes, by gnawing and eating these things.
The larva of beetles looks like the larva of butterflies. It has no wings. No larva ever has wings.
The change of getting wings must come when the larva has gone into the pupa cradle. ”

“ When it is full-fed, and about to enter the pupal state, it proceeds to prepare its habitation. As a larva, when it desired to feed, it protruded its head and the front of its body from the mouth of the tube, and then crawled about in search of nourishment, dragging the tube with it, and holding it firmly by means of the claspers with which the end of the body is furnished. But when it becomes a pupa it is no longer able to defend itself, and is instinctively compelled to secure its safety in some peculiar manner. ”

“ Imagine one of your arms being joined on to your chin, bend your elbow up till your hand covers your face—this will represent the dragon larva with the mask in repose; now shoot out your arm in a straight line from the head—this will represent the mask unfolded and in use; your fingers may be considered to represent the jaws of the creature. When the larva wishes to turn into an insect, it leaves the water and creeps up the stem of some water weed or other object out of the water, bursts its skin, and commences its new state of existence. ”

“ Laparostict: that series of lamellicorn beetles in which the abdominal spiracles are situated on the connecting membrane between the dorsal and ventral rings.
Lapidicolous: living under deeply imbedded stones.
Larva: the second stage of insect development; comes from the egg or ovum, grows, and according to its kind, changes to a pupa or chrysalis or to an imago ”

“ Why does the larva grow up to a certain period with great rapidity, then cease its appropriating power and break up the parts that have been so rapidly and recently formed? And why do the imaginal buds remain quiescent till the other tissues are being disintegrated, and then, instead of sharing the general condition of disintegration, commence a career of development? ”

“ The immature larva is reddish brown with narrow yellowish lines that extend the length of the body. The full-grown larva is almost black with two grayish lines on the back and two on the sides. Many long, soft gray hairs are distributed over the body. ”

“ It is the rule that, when the cells of the comb are only partially formed, eggs are deposited in them, and that the larva resulting from the egg is fed and tended by the mother, or by her assistants, the workers; as the larvae grow, the cells are increased in correspondence with the size of the larva; the subsequent metamorphosis to pupa and imago taking place in the cells after they have been entirely {79}closed. The food supplied is of a varied nature according to the species, being either animal or vegetable, or both. ”

“ A large part of the substance of an insect larva consists of muscular tissue, surrounding the digestive tube, and forming the great muscles that move the various parts of the body, and of fat, surrounding the organs and serving as a store of food-material. Very many of the muscle-fibres and the fat-cells also become disintegrated during the late larval and pupal stages, and the corresponding tissues of the adult are new formations derived from special groups of imaginal cells, though some muscles may persist from the larva to the adult. ”

“ Since larva are distributed through at least three elements, being, according to the species, inhabitants of earth, air, and water, the breathing apparatus arrests our attention, as constituting a distinct feature in the anatomy of the insect. A caterpillar may be regarded as all stomach, and the cravings of this immense digesting tube easily account for the voracity of larva of all kinds. ”

“ Although it voids no excrement till much later the union of the stomach and hind-intestine is accomplished when the larva is half-grown. A larva, from which Müller took away a portion of its unconsumed food-store, began directly afterwards to emit excrement. The pupa has greater power of movement than the resting larva; when it has completed its metamorphosis and become a perfect Insect, it, if it be a female, commences almost immediately after its emergence to form burrows by the complex and perfect series of actions we have described. ”

“ The larva strength ens this capping by a loose webwork of silk within, extending down the side but slightly and attached at its edges to the last skin cast by the molting larva. This skin, extremely delicate and pressed closely against the inside of the cell, forms the lining of its sides and bottom. ”

“ Since it has been shewn that the larva or caterpillar is really the moth, crawling, eating, and spinning, under the form of the worm, and that the pupa is only the moth swathed up, it is clear that they are not three beings, but that the same individual feels, tastes, sees, and acts by different organs, at different periods of its life, having sensations and wants at one time, which it has not at another ”

“ The larva A will reach its full development—it will be a queen-bee; the larva B, on the other hand, not having food enough for all its wants, and furthermore having within a given time to change its conditions, it must use the nutriment for the building up of its more important organs, must work it up into tissues and structures that are essential to all bees. Its head, body, legs, and wings must be perfected before its reproductive system; the individual must profit before the race ”

“ In the latter case the larva crawls about the bottom of the water or up the stems of plants, with its thickly-chitinized head and legs protruding from the larger orifice, while it maintains a secure hold of the silk lining of the tube by means of a pair of strong hooks at the posterior end of its soft defenceless abdomen. Their food appears for the most part to be of a vegetable nature. ”

“ When the larva wishes to descend, a stroke of the tail sends it downwards, and as it reaches the bottom of the tube it will cling with its claws to any weed we may have put in with it, or hold on with them to the glass itself. ”

“ The entire organism, of course, is hot double, for, as we have just seen in the study of the caterpillar, many of the more vital organs are continuous from the larva to the adult; but there is a group of organs which, after reaching a definite form of development in the larval stage, at the end of this stage virtually die and go into dissolution, while a new set of tissues develops into new organs or into new tissues replacing those that have been lost. ”

“ Although no legs are visible in the adult larva, they really arise very early in the larval life from masses of hypodermis, and grow in the interior of the body, so that when the larva is adult the legs exist in a segmented though rudimentary condition in the interior of the body. ”

“ When the whole of the fluid in the interior of the egg has been assimilated, and the young larva matured, it emerges either by rupturing the envelope, gnawing it asunder, or pushing open a kind of moveable lid at the end, constructed apparently for the express purpose of facilitating its exit.
Larva. Insects as often present themselves to our notice in this stage of their existence as in their perfect state, and not unfrequently attract our attention by their depredations on the produce of our fields and gardens. ”

“ They are always associated with a small egg in which the amount of food yolk is not sufficient to enable the animal to complete its development in the embryonic state. (2) A free-swimming larva is usually found in cases in which the adult is attached to foreign objects. (3) A larval stage is, as a rule, associated with internal parasitism of the adult. The object gained by the occurrence of a larva in the two last cases is to enable the species to distribute itself over as wide an area as possible. ”

“ When the growth is completed the larva returns to land, seeks a suitable situation in the soil, and after an interval changes to a pupa, in which the characters of the perfect Insect are plainly visible. Subsequently, without becoming again active, it changes to the perfect Insect, and enjoys, for a few days only, an aerial life. ”

“ Larva.
Until very recently the life-history of this parasite was unknown but the thorough work of Ransom (1911, 1913) has shown clearly that the adult stage occurs in the stomach of horses. The embryos, produced by the parent worms in the stomach of the horse, pass out with the feces and enter the bodies of fly larvæ which are developing in the manure. In these they reach their final stage of larval development at about the time the adult flies emerge from the pupal stage. In the adult fly they are commonly found in the head. ”

“ Thus also, not being so much needed in larval life before the reproductive organs are developed, they would not be transmitted except in a very rudimentary way, as perhaps masses of internal indifferent cells (imaginal discs) , to the larva, being the rather destined to develop late in larval and in pupal life. Thus the development of the wings and of the generative organs would go hand in hand, and become organs of adult life. ”