Its condition thus recalls the pupal instar of the higher (Endopterygote) Hexapoda; and the Thysanoptera, though few in number, are seen to be of great interest to the student, exhibiting at once a transition between the biting and the suctorial mouth, and the passage from " incomplete " to " complete " metamorphosis.
After another moult the insect passes into the passive nymphal or " pupal " stage, during which it takes no food and rests in some safe hiding-place, such as the soil at the base of its food-plant or the hollow of a leaf-stalk.
Some members of this order spend the winter in the adult state, others in the " larval " or " pupal " condition.
In this it remains until the completion of the transformation into the sexually mature insect, which then emerges from the case, leaving the pupal integument behind.
Meinert, who endeavoured to compare them with the tegulae of Hymenoptera, but the older view was securely established by the demonstration in pupal elytra by J.
As regards growth after hatching, all beetles undergo a "complete" metamorphosis, the wing-rudiments developing beneath the cuticle throughout the larval stages, and a resting pupal stage intervening between the last larval instal1 and the imago.
The pupal stage is passed in an earthen cell, just beneath the surface of the ground.
After a resting (pseudo-pupal) stage and another larval stage, the pupa is developed.
This is followed by a resting (pseudo-pupal) stage, and thisby two successive larval stages like the grub of a chafer.
The wasps are said to leave the larval or pupal Metoecus unmolested, but they are hostile to the developed beetles, which hasten to leave the nest as soon as possible.
In this way it is believed that the sub-aqueous cocoon in which the pupal stage is passed becomes filled with air.
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.
These insects pass the pupal stage in the ground, and reach the boughs to lay their eggs by crawling up the trunks of the trees.
These breed plu m; E, pupal stage.
Hexapoda with this resting pupal stage in their life-history are said to undergo " a complete transformation," to be metabolic, or holometabolic, whereas those insects in which the young form resembles the parent are said to be ametabolic. Such insects as dragon-flies and may-flies, whose young, though unlike the parent, develop into the adult form without a resting pupal stage are said to undergo an " incomplete transformation " or to be hemimetabolic. The absence of the pupal stage depends upon the fact that in the ametabolic and hemimetabolic Hexapoda the wing-rudiments appear as lateral outgrowths (fig.
In the metabolic Hexapoda the resting pupal instar shows externally the wings and other characteristic imaginal organs which have been gradually elaborated beneath the larval cuticle.
Young animals always unlike parents, the wing-rudiments developing beneath the larval cuticle and only appearing in a penultimate pupal instar, which takes no food and is usually passive.
And thus perfection of structure and instinct in the imago has been accompanied by degradation in the larva, and by an increase in the extent of transformation and in the degree of reconstruction before and during the pupal stage.
Swammerdam, however, showed the presence under the larval cuticle of the pupal structures.
The reproduction of tsetse-flies is highly remarkable; instead of laying eggs or being ovovivi parous the females deposit at intervals of about a fortnight or three weeks a single full-grown larva, which forthwith buries itself in the ground to a depth of several centi metres, and assumes the pupal state.
Before passing into the pupal stage, the larva partially closes the orifice of the tube with silk or pieces of stone loosely spun together and pervious to water.
Through this temporary protection the active pupa, which closely resembles the mature insect, subsequently bites a way by means of its strong mandibles, and rising to the surface of the water casts the pupal integument and becomes sexually adult.
The other groups of the old Linnean order (such as lacewing-flies and caddis-flies)--which are hatched as larvae markedly unlike the parent, develop wing-rudiments hidden under the larval cuticle, and only show the wings externally in a resting pupal stage, passing thus through a " complete " metamorphosis and falling into the sub-class Endopterygotawere retained in the order Neuroptera, which thus became much restricted in its extent.
The insects retained in the order Neuroptera as restricted by modern systematists are distinguished from the preceding orders by the presence of a resting pupal stage in the life-history, so that a " complete metamorphosis " is undergone.
Finally the larva of one of the Bornean Mantidae, which is a floral simulator in its pupal and adult stages, closely resembles in its black and red coloration the larva of the stinking and warningly coloured bug Eulyes amoena.
When fullsized they leave the water and spend a quiescent pupal stage on the land before metamorphosis into the sexually mature insect.
When a young queen has emerged, she stings her royal sisters (still in the pupal stage) to death.