Thus myriads of irritant particles are disseminated and subtly introduced into every part of the nest. The shirt of Nessus burnt the veins of whoso wore it; the silk of the Processionary, another poisoned fabric, sets on fire the fingers that handle it. The loathsome hairs long retain their virulence. I was once sorting out some handfuls of cocoons, many of which were diseased. As the hardness of the contents was usually an indication that something was wrong, I tore open the doubtful cocoons with my fingers, in order to save the non-contaminated chrysalids. My sorting was rewarded with the same kind of pain, especially under the edges of the nails, as I had already suffered when tearing the nests. The cause of the irritation on this occasion was sometimes the dry skin discarded by the Processionary on becoming a chrysalis and sometimes the shrivelled caterpillar turned into a sort of chalky cylinder through the invasion of the malignant fungus. Six months later, these wretched cocoons were still capable of producing redness and irritation. Examined under the microscope, the russet hairs, the cause of the itching, are stiff rods, very sharp at either end and armed with barbs along the upper half. Their structure has absolutely nothing in common with nettle-hairs, those tapering phials whose hard point snaps off, pouring an irritant fluid into the tiny wound. The plant from whose Latin name, Urtica, we derive the word urtication borrowed the design of its weapon from the fangs of the venomous serpents; it obtains its effect, not by the wound, but by the poison introduced into the wound. The Processionary employs a different method. The hairs, which have naught resembling the ampullary reservoir of the nettle-hairs, must be poisoned on the surface, like the assegais of the Kafirs and Zulus. Do they really penetrate the epidermis? Are they like the savage’s javelin, which cannot be extracted once it has gone in? With their barbs, do they enter all the more deeply because of the quivering of the outraged flesh? There is no ground for believing anything of the kind. In vain do I scrutinize the injured spot through the magnifying-glass; I can see no sign of the implanted dart. Neither could Réaumur, when an encounter with the Oak Processionary set him scratching himself. He had his suspicions, but could state nothing definitely. No; despite their sharp points and their barbs, which make them, under the microscope, such formidable spears, the Processionary’s russet hairs are not darts designed to imbed themselves in the skin and to provoke irritation by pricking. Many caterpillars, all most inoffensive, have a coat of bristles which, under the microscope, resolve themselves into barbed javelins, quite harmless in spite of their threatening aspect. Let me mention a couple of these peaceable halberdiers.