The worm inhabits the lung of the frog and toad, and is hermaphrodite (Schneider) or parthenogenetic (Leuckart); the embryos hatched from the eggs find their way through the lungs into the alimentary canal and thence to the exterior; in a few days they develop into a sexual larva, called a Rhabditiform larva, in which the sexes are distinct; the eggs remain within the uterus, and the young when hatched break through its walls and live free in the perivisceral cavity of the mother, devouring the organs of the body until only the outer cuticle is left; this eventually breaks and sets free the young, which are without teeth, and have therefore lost the typical Rhabditis form.
Without a hydroid phase; the medusa develops directly from the actinula larva, which may, however, multiply by budding.
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 full-grown larva digs a pit about 2 in.
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.
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 carabid larva is an active well-armoured grub with the legs and cerci variable in length.
The beetles are fierce Antenna of Larva of Gyrinus.
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.
Larva, or mealworm.
The growth of the parasitic larva does not stop the development of the host-larva, and when the latter pupates and assumes the winged form, the stylopid, which has completed its transformation, is carried to the outer world.
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.
The larva pierces the vessels of the plant with sharp processes at the hinder end of its body.
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.
- A, Side view of the larva of Lopadorhynchus (from Kleinenberg), showing the developing trunk region.
B, Side view of the trochophore larva of Eupomatus uncinatus (from Hatschek).
This larva is termed the Trochosphere larva, and typically (as it is held) is an egg-shaped larva with two bands of cilia, one preoral and one postoral, with an apical nervous plate surmounted by a tuft of longer cilia, and with a simple bent alimentary canal, with lateral mouth and posterior anus, between which and the ectoderm is a spacious cavity (blastocoel) traversed by muscular strands and often containing a larval kidney.
The chief modifications of this form are seen in the Mitraria larva of Ammochares with only the preoral band, which is much folded and which has provisional and long setae; the a.trochous larva, where the covering of cilia is uniform and not split into bands; and the polytrochous larva where there are several bands surrounding the body.
One species, the slugworm (Eriocampa liynacina), is common to Europe and America; the larva is a curious slug-like creature, found on the upper surface of the leaves of the pear and cherry, which secretes a slimy coating from its skin.
2, C): the larva therefore resembles Nautilus in the relations of body and shell.
The pallial cavity, with its organs, is by this torsion moved up the right side of the larva to the dorsal surface, and thus the left organs become right and vice versa.
In those Euthyneura in which the shell is entirely absent in the adult, it is, except in the three genera Cenia, Runcina and Vaginula, developed in the larva and then falls off.
A, Veliger-larva of an Opisthobranch (Polycera).
The gross feeder is a man in the larva state; and there are whole nations in that condition, nations without fancy or imagination, whose vast abdomens betray them.