in walking they oppose no resistance to the progress of the caterpillar, which they would do were they attached in the opposite direction, or without method. Cases of considerable size are armed with large pieces of leaf in similar fashion. It will be observed that these twigs, or leaves, as the case may be, are arranged somewhat systematically, the base of those nearest the narrow extremity lying beneath those nearer the wider aperture, or mouth, showing the latter to have been added subsequently, proving, in fact, that the case is gradually manufactured in the direction of its mouth. Through this the larva habitually puts its head. It is thus easy enoucrh for it to extend its dwellinor n this direction while resident within it, though it necessarily exposes itself to a considerable extent in applying the twigs or leaves to the outside. The leather-like case of Aninmla hcri'ichii is of remarkable construction, in that the external surface is destitute of any extraneous matters.

As a larva grows, needing more accommodation, it splits the habitation at the sides, weaving into the opening portions of the vegetable substances selected, and adding to the exterior fresh pieces of stick, straw, or leaves, as it requires. So with Saunders' Case Moth, when any accident happens to the nest, the caterpillar, with incredible expedition, repairs the damage received, employing the same silky stuff to fill up the hole; and

with a nicety so perfect that the severest scrutiny cannot detect what was the extent of the injury.

Under the protection, then, of the substantial and somewhat formidable case the larva lives. At each end there is an opening, and through the anterior one it emerges to feed and change its position. Commonly, it only protrudes the head and the first three or four segments of the body, or sufficient to use its six true legs for locomotion when feeding; and if wishful to remain quiet, it usually takes the precaution of fastening a portion of the edge of the aperture by fibres of silk temporarily to the branch upon which it is, that, if alarmed, it can suddenly recede completely into the case, very rapidly drawing in the fiexible part after it, by means of its mandibles and forelegs, and contracting the aperture so as to exclude all enemies. Thus hid, it stays in security, suspended only by a few threads. Were the nature of the hanging, tight-closed, strong, tough sack unknown, it would never be suspected of containing an active, voracious larva. Exceedingly wary and timid are these insects in retreating at the approach of danger. On a desire for removal, the suspending threads are bitten off close to the case.

As long as the caterpillar is small, and the house of no great weight, it is borne nearly erect, but soon, as a rule, the incumbent mass lies flat, owing to Increased weight, and is dragged along in that attitude. The

2ii THE CASE MOTHS (PSYCHID^).

abdominal and anal le^s of the larva are furnished with a series of small points or hooks, with which it moves in the tube, laying hold of the interior of the lining, to which it can adhere with great pertinacity; so firm is the hold retained, it is impossible to remove the creature without injury.

Coining of Age.

Having attained full growth, and being about to change to pupa, the larva of Metura saundcrsii firmly fixes itself, by means of silken fibres, spun for the purpose, to a branch or trunk of a tree, or paling, drawing together and permanently closing the head opening. It reverses its position in the case, so that the head is where the tail used to be, pointed towards the posterior or unattached end, and envelopes itself in a soft silken cocoon, of a yellowish colour. Allowing itself to hang perpendicularly, head downwards, it awaits the pupal sleep. From the facts just stated, it need hardly be said that, when the time arrives, the perfect insect emerges from the posterior portion of the tube. At this particular time the male pupa becomes endowed with the power of stretching out its segments, to enable it to work its way out of the extremity. Through the opening of the posterior end it pushes the anterior half of its length by

a slight elongation and contraction of the body, which, with the assistance of a transverse series of minute sharp spines or hooks, directed backwards, on some of the segments, is in this way forced out head foremost, in like manner as the pupa^ of the Goat Moths and the large Swifts are made to emerge from timber and the earth, when the moth is ready to escape. The pupae are prevented from being thrust entirely out of the case by two strong anal hooks. After the issue of the imago, the segments remain in their stretched-out condition. Cases havinof belono-ed to males are often seen with the empty pupa skin sticking rather more than half out of the lower aperture, hanging head downwards, as left by the moth. It will be observed, both in the present species and the Lictor Moth, as in others, that there are, as I have shown, in most of the cases, one or two pieces of twigs longer than those of which the remainder of the case is composed, and extending posteriorly some distance beyond the termination of the fabric. Possibly these may be intended to assist the male, on entering the perfect state, to effect his exit from the case, the twig affording foothold, and aiding the imago to draw his long abdomen out of the pupa skin. The males of these moths are swift flyers of extraordinary activity, dashing themselves wildly, almost to pieces, among the branches of the trees. A fiery little

creature has no sooner arisen from his pupal slumber than he beo^ins his violent flutterinc^, and as the wing-s are delicate in structure, in many instances nearly transparent, his beauty has generally disappeared before the entomologist can secure him, and specimens in good order are rare in collections. With slight exception, we find no homogeneousness in the perfect state of the insects of this group, but much variation of form

Fig. 40.—Male and female Mctio-a clongcta.

presented by the different species. The general shape of the body varies from one greatly elongated, as in Metitra elongata, in Dappiila tertia, and Oiketicus kh'bii, to a short and robust, as well as to a short and slender form. In like manner the wings vary from a long, narrow, and sharp-pointed wing, as in Metura, to a wing of short, broad, and ample proportions; and again, may either be densely squamose, or colourless, of beautiful hyaline texture, almost or completely destitute of scales or hairs. The antennce may be deeply pectinated only

at the base, in others they are feathered to the tip; and in the number of joints offer striking variations (see

Fig. 40).

Probable Cause of Disappearance of Beauty.

But the males of nearly all Psychidae are characterized by a uniform dull dark colour of a brown or grey tint; there is an almost total absence of bright colour or of pattern. Yet these moths are in nearly all cases day-flying. Probably the beauty of the males disappears when the females become degenerate, and the conditions which produced it are then at an end. In other species of Bombyces in which the degeneracy of the females is less complete, less pronounced is the attendant loss of colour by the males. The day-flying Bombyces, whose females retain full possession of their faculties, are remarkable for the brightness and beauty of their colours."

Singular Rarity of Moths considering Abundance of Cases.

The larval cases of these moths are amongst the " common objects " in Australia, meeting the eye every-

Poulton, ' The Colours of Animals."

where suspended to trees and shrubs, such as the different kinds of Leptospermum, Melaleuca, etc., fixed by their anterior end, and swinging loose otherwise. When unusually abundant, so as to look like a good crop of some seed or fruit, the pendant berths are particularly conspicuous, and attract the attention of the least curious of mortals. The most striking examples of the group belong to Metiwa saundersii, whose cases are sometimes over five inches long; those of the male are one-third smaller; but if this kind far exceeds any of the others in size, the case of the Lictor Moth bears off the palm for excessive abundance. The latter species chiefly frequents the Eucalypti, or Gum-trees so-called, but may also be found plenteously on many others of diverse botanical characters. Considering this abundance, the insects are singularly rare in the moth state; not one case in a hundred will be found to produce a moth, owing, partly, to the destructive effects of attacks on the larvce of Ichneumo-nideous and Dipterous parasites; even the Lictor Moths are surprisingly difficult to procure. From the same cause, nothing is harder, nay, more nearly impossible, it may be mentioned, than to rear these creatures in confinement. The caterpillars of a species may be collected persistently for years, and watched with incessant care, and yet never reach the perfect stage. Hence there are already imperfectly known species of which the more

2i6 TRUE TALES OF THE INSECTS.

mature conditions await discovery; and when success does attend our efforts at protection, many examples are probably observed of the depredations of the insidious parasites. Not that failure to attain perfection is always due to infestation of parasitic insects, as undoubtedly the somewhat ponderous houses of the larvse render them to a high degree impervious to the onslaughts of insect enemies: the cause of death must be looked for elsewhere. Death usuall}^ occurs after the larva has undergone metamorphosis, the pupa gradually shrivelling up after assuming its proper form, nor can anything be done, apparently, to avert the calamity.

A Perpetual Prisoner.

To return to the Case Moths' metamorphoses. The female insect, as we have seen, unlike the male, is destined never to desert the larval home. For her no hour of emergence ever comes. When the pupa has slept the appointed time, the unwieldy and almost motionless moth feels little of the movement of oncoming life then experienced by her lithe and lively partner; the animal, still resident within the habitaculum formed by the larva, splits asunder the pupa skin, and her transformations are complete: in some, at least, of the species the female imago is continually

enclosed in the pupa case. Here, therefore, we have an insect which in its adult state is for ever excluded from the light, and never even beholds its mate.

In many of the genera the female is of the most dege-grub-like thing, the head,nerate type—a mere bag, a thorax, and abdomen hardly distinguishable from each other; without limbs or sense organs; totally unprovided with wings, legs, antenn;^;, or eyes. In the pupa case of these forms no distinct trace of former organs can be ; in others they appear in a very rudimentarymade out condition; in others again, still more distinctly. Observe the amount of development in two forms already mentioned, Oikcticus kirhii and Oiketicus saundersii. We see the ordinary grub-like appearance in the first, the three great divisions of the body being scarcely defined, and the whole enclosed in a tough envelope. Here exist neither tongue, palpi, nor antennae,* no wings, and all but obsolete unarticulated feet: the general colour of the body is brownish; the neck and anus are clothed with wool-like hairs. Turn to Metiira sawidersii, about one and three-quarter inches in length, and in diameter full half an inch; cylindrical; of a pale brownish cream-colour, the head and thoracic segments light brown, fleshy, and smooth, the terminal segments clothed all round with dense silky down, of a deeper colour than the rest of the body. The insect is apterous, her antenna

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