We have just discovered (Nov. 4th, 1829) upon the nettle a tent of a very singular appearance, in consequence of the materials of which it is made. The caterpillar seems, indeed, to have proceeded exactly in the same manner as those which we have described, mining first between the two membranes of the leaf, and then uniting these and cutting out his tent. But the tent itself looks singular from being all over studded with the stinging bristles of the nettle, and forming a no less formidable coat of mail to the little inhabitant than the spiny hide of the hedgehog. In feeding it does not seem to have mined into the leaf, but to have eaten the whole of the lower membrane, along with the entire pulp, leaving nothing but the upper membrane untouched. (J. R.) During the summer of 1830 we discovered a very large tent which had been formed out of a blade of grass; and another stuck all over with chips of leaves upon the common maple.
a, The Caterpillar occupying the space it has eaten
between the cuticles of the leaf;
b, a portion of the upper cuticle, cut out for the
formation of the tent;
c, the tent nearly completed;
d, the perfect tent, with the caterpillar protruding its head.
Tents of Stone-Mason Caterpillars.
The caterpillar of a small moth (Tinea) which feeds upon the lichens growing on walls, builds for itself a moveable tent of a very singular kind. M. de la Voye was the first who described these insects; but though they are frequently overlooked, from being very small, they are by no means uncommon on old walls. Réaumur observed them regularly for twenty years together on the terrace-wall of the Tuileries at Paris; and they may be found in abundance in similar situations in this country. This accurate observer refuted by experiment the notion of M. de la Voye that the caterpillars fed upon the stones of the wall; but he satisfied himself that they detached particles of the stone for the purpose of building their tents or sheaths (fourreaux), as he calls their dwellings. In order to watch their mode of building, Réaumur gently ejected half-a-dozen of them from their homes, and observed them detach grain after grain from a piece of stone, binding each into the wall of their building with silk till the cell acquired the requisite magnitude, the whole operation taking about twenty-four hours of continued labour. M. de la Voye mentions small granular bodies of a greenish colour, placed irregularly on the exterior of the structure, which he calls eggs; but we agree with Réaumur in thinking it more probable that they are small fragments of moss or lichen intermixed with the stone: in fact, we have ascertained that they are so. (J. R.)
Lichen-Tents and Caterpillars, both of their natural size and magnified.
When these little architects prepare for their change into chrysalides before becoming moths, they attach their tents securely to the stone over which they have hitherto rambled, by spinning a strong mooring of silk, so as not only to fill up every interstice between the main entrance of the tent and the stone, but also weaving a close, thick curtain of the same material, to shut up the entire aperture.
It is usual for insects which form similar structures to issue, when they assume the winged state, from the broader end of their habitation; but our little stone-mason proceeds in a different manner. It leaves open the apex of the cone from the first, for the purpose of ejecting its excrements, and latterly it enlarges this opening a little, to allow of a free exit when it acquires wings; taking care, however, to spin over it a canopy of silk, as a temporary protection, which it can afterwards burst through without difficulty. The moth itself is very much like the common clothes-moth in form, but is of a gilded-bronze colour, and considerably smaller.