Remember that the sticky coat in which the grub is clad does not dry up: this is a condition indispensable to liberty of movement. If changed into a hard varnish, a dry film, it would hamper, would indeed stop the crawling; but, so long as it remains liquid, it is the drop of oil that lubricates the locomotory machine. This moist coating will, however, constitute the material of the nymphosis-bladder: the fluid will become gold-beater’s-skin, the liquid will solidify. This change of condition at first suggests oxidation. We must abandon this idea. If the hardening were really the result of oxidization, the grub, being sticky from its birth and always exposed to the air, would long ago have been clad not in a delicate coat of adhesive, but in a stiff parchment sheath. Desiccation obviously must take place at the last moment and rapidly, when the grub is preparing to change its shape. Before then, this desiccation would be a danger; now, it is an excellent means of defence. To ‘fix’ oil-paintings our ingenuity employs siccatives, that is to say, ingredients that act upon the oil, giving it a resinous consistency. The Cionus likewise has its siccative, as the following facts prove. It may be that the grub was labouring to produce this desiccating substance, by some profound change in the process of its organic laboratory, at the time when its poor flesh was quivering with feverish tremors; it may be that it was proceeding to spread the siccative over the whole surface of its body by taking a long walk, the last of its larval life. 7 P.M.—The larva is once more motionless, lying flat on its belly. Is this the end of its preparations? Not yet. The globular structure must have a foundation, a base on which the grub can support itself in order to dilate its ampulla. 8 P.M.—Round the head and the fore-part of the thorax, which, like the rest of the body, are touching the slip of glass, a border of pure white now appears, as though snow had fallen at these points. This forms a sort of horse-shoe enclosing an area in which the snowy deposit is continued in a vague mist. From the base of this border some threads of the same white substance radiate in short tufts. This structure denotes work done with the mouth, a miniature wire-drawing. And in fact no such white substance is seen anywhere except around the head. Thus the creature’s two ends take part in the building of the hut: the one in front provides the foundations, the one behind provides the edifice.