Fabre's Book of Insects

by Jean-Henri Fabre

This is the secret of the walking bundle of sticks. It is a Faggot belonging to the group known as the Psyches

In April, on the walls of my chief workshop—my stony harmas with its wealth of insect life—I find the Psyche who will supply me with my most detailed information. He is in the torpid state which shows he will soon become a Moth. It is a good opportunity for examining his bundle of sticks, or case.

It is a fairly regular object, shaped like a spindle, and about an inch and a half long. The pieces that compose it are fixed in front and free at the back. They are arranged anyhow, and would form rather a poor shelter against the sun and rain if the hermit had no other protection than this.

At the first glance it appears like thatch; but thatch is not an exact description of it, for grain-stems are rarely [[91]]found in it. The chief materials are remnants of very small stalks, light, soft, and rich in pith; next in order come bits of grass-leaves, scaly twigs from the cypress-tree, and all sorts of little sticks; and lastly, if the favourite pieces run short, fragments of dry leaves.

In short the Caterpillar, while preferring pithy pieces, will use anything he comes across, provided it be light, very dry, softened by long exposure, and of the right size. All his materials are used just as they are, without any alterations or sawings to make them the proper length. He does not cut the laths that form his roof; he gathers them as he finds them. His work is limited to fixing them at the fore-end.

In order to lend itself to the movements of the travelling Caterpillar, and particularly to enable the head and legs to move freely while a new piece is being fixed in position, the front part of this case or sheath must be made in a special way. Here a casing of sticks is no longer suitable, for their length and stiffness would hamper the workman and even make his work impossible. What is required here is a flexible neck, able to move in all directions. The collection of stakes, therefore, ends suddenly at some distance from the fore-part, and is there replaced by a collar where the silk lining is merely hardened with very tiny particles of wood, which strengthen the material without making it less flexible. [[92]]This collar, which allows of free movement, is so important that all the Psyches use it, however greatly the rest of their work may differ. All carry, in front of the bundle of sticks, a yielding neck, soft to the touch, formed inside of a web of pure silk and coated outside with a velvety sawdust, which the Caterpillar obtains by crushing up any sort of dry straw.

The same kind of velvet, but dull and faded—apparently through age—finishes the sheath at the back, in the form of a rather long projection, open at the end.

When I remove the outside of the straw casing, shredding it piece by piece, I find a varying number of laths, or tiny sticks. I have counted as many as eighty, and more. Underneath it I find, from one end of the Caterpillar to the other, the same kind of inner sheath that was formerly visible at the front and back only. This inner sheath is composed everywhere of very strong silk, which resists without breaking when pulled by the fingers. It is a smooth tissue, beautifully white inside, drab and wrinkled outside, where it bristles with a crust of woody particles.

Later on we shall see how the Caterpillar makes himself this complicated garment, formed of three layers, one placed upon the other in a definite order. First comes the extremely fine satin which is in direct contact [[93]]with the skin; next, the mixed stuff dusted with woody matter, which saves the silk and gives strength to the work; and lastly the outer casing of overlapping sticks.

Although all the Psyches wear this threefold garment, the different species make distinct variations in the outer case. There is one kind, for instance, whom I am apt to meet towards the end of June, hurrying across some dusty path near the houses. His case surpasses that of the first species, both in size and in regularity of arrangement. It forms a thick coverlet of many pieces, in which I recognise fragments of hollow stalks, bits of fine straw, and perhaps blades of grass. In front there is never any flounce of dead leaves, a troublesome piece of finery which is pretty frequent, though not always used, in the costume of the first species I described. At the back there is no long projection beyond the outer covering. Save for the indispensable collar at the neck, the whole Caterpillar is cased in sticks. There is not much variety about the thing, but, when all is said, there is a certain beauty in its stern faultlessness.