The irritation set up by the hatching egg and its resulting larva appears to be the stimulus to development, and net a poison or enzyme injected by the insect.
A, Veliger-larva of an Opisthobranch (Polycera).
A, Beetle; b, head of beetle with feelers and palps; c, larva; d, pupa.
Extremes we find various transitional forms: an active larva, as described above, but with four-segmented, single-clawed legs, as among the rove-beetles and their allies; the body well armoured, but slender and worm-like, with very short legs as in wireworms and mealworms (figs.
The female is viviparous, and the young, which, unlike the parent, are provided with a long tail, live free in water; it was formerly believed from the frequency with which the legs and feet were attacked by this parasite that the embryo entered the skin directly from the water, but it has been shown by Fedschenko, and confirmed by Manson, Leiper and others, that the larva bores its way into the body of a Cyclops and there undergoes further development.
Without a hydroid phase; the medusa develops directly from the actinula larva, which may, however, multiply by budding.
The reproductive organs do not begin to appear until the larva has twice cast its skin.
It is absurd to call the larva of a newt or of a Caecilian a tadpole, nor is the free-swimming embryo of a frog as it leaves the egg a tadpole.
A tadpole is the larva of a tailless Batrachian after the loss of the external gills and before the egress of the fore limbs (except in the aberrant Xenopus) and the resorption of the tail.
When the latter is reached and the pit completed, the larva settles down at the bottom, buried in the soil with only the jaws projecting above the surface.
The larva makes a globular case of .sand stuck together with fine silk spun, it is said, from a slender spinneret at the posterior end of the body.
Larva of Dyticus Cybister sp. (Water-Beetle).
The most striking feature in the development of beetles is the great diversity noticeable in the outward form of the larva in different families.
A, Calandra granaria; b, larva; c, pupa; d, C. oryzae.
Similarly the newly-hatched larva of an oil-beetle (Meloe) is an active little campodeiform insect, which, hatched from an egg laid among plants, waits to attach itself to a passing bee.
Sharp; in the stag-beetle larva a series of short tubercles on the hind-leg is drawn across the serrate edge of a plate on the haunch of the intermediate legs, while in the Passalid grub the modified tip of the hind-leg acts as a scraper, being so shortened that it is useless for locomotion, but highly specialized for producing sound.
The generalized arrangement of the wing-nervure and the nature of the larva, which is less unlike the adult than in other beetles, distinguish this tribe as primitive, although the perfect insects are, in the more dominant families, distinctly specialized.
With very few exceptions, the larva in this group is active and campodeiform, with cerci and elongate legs as in the Adephaga, but the leg has only four segments and one claw.
The "` bacon beetle" (Dermestes lardarius), and its hard hairy larva, are well known.
The first larval stage is the "triungulin," a tiny, active, armoured larva with long legs (each foot with three claws) and cercopods.
After eating the contents of the egg, the larva moults and becomes a fleshy grub with short legs and with paired spiracles close to the dorsal region, so that, as it floats in and devours the honey, it obtains a supply of air.
In the American Epicauta vittata the larva is parasitic on the eggs and eggcases of a locust.
Clinging to her hairs they are carried to the nest, where they bore into the body of a bee or wasp larva, and after a moult become soft-skinned legless maggots.
Among the vegetable-feeding chafers we usually find that while the perfect insect devours leaves, the larva lives underground and feeds on roots.
The most active form of larva found in this family resembles in shape that of a ladybird, tapering towards the tail end, and having the trunk segments protected by small firm sclerites.
Riley, who finds that the young larva, hatched from the egg laid on the pod, has three pairs of legs, and that these are lost after the moult that occurs when the grub has bored its way into the seed.
Mosquitoes go through four phases: (1) ovum, (2) larva, (3) nympha, (4) complete insect.
The larva has no breathing-tube, and floats horizontally at the surface, except when feeding; it does not frequent sewage or foul water.
The larva has a breathing-tube, and floats head downwards; when disturbed it wriggles to the bottom (Christy).
In these forms the pregnant female, instead of laying eggs, as Diptera usually do, or even producing a number of minute living larvae, gives birth at one time but to a single larva, which is retained within the oviduct of the mother until adult, and assumes the pupal state immediately on extrusion.
A, Female; b, female after loss of wings; c, male; d, worker; e, larva; g, pupa (magnified four times); f, head of larva more highly magnified.
- A, Side view of the larva of Lopadorhynchus (from Kleinenberg), showing the developing trunk region.