The two ends of the ellipsoid have the same form, so much so that it is only thanks to an individual peculiarity, independent of the shape, that we can tell the cephalic from the anal extremity. The cephalic pole is flexible and yields to the pressure of my tweezers; the anal pole is hard and unyielding. The wrapper is double, as in the cocoons of the Sphex. (Cf. "The Hunting Wasps": chapters 4 to 10 et passim.--Translator's Note.) The outer envelope, consisting of pure silk, is thin, flexible and offers little resistance. It is closely superimposed upon the inner envelope and is easily separated from it everywhere, except at the anal end, where it adheres to the second envelope. The adhesion of the two wrappers at one end and the non-adhesion at the other are the cause of the differences which the tweezers reveal when pinching the two ends of the cocoon. The inner envelope is firm, elastic, rigid and, to a certain point, brittle. I do not hesitate to look upon it as consisting of a silken tissue which the larva, towards the end of its task, has steeped thoroughly in a sort of varnish prepared not by the silk-glands but by the stomach. The cocoons of the Sphex have already shown us a similar varnish. This product of the chylific ventricle is chestnut-brown. It is this which, saturating the thickness of the tissue, effaces the bright red of the beginning and replaces it by a brown tint. It is this again which, disgorged more profusely at the lower end of the cocoon, glues the two wrappers together at that point. The perfect insect is hatched at the beginning of July. The emergence takes place without any violent effraction, without any ragged rents. A clean, circular fissure appears at some distance from the top; and the cephalic end is detached all of a piece, as a loose lid might be. It is as though the recluse had only to raise a cover by butting it with her head, so exact is the line of division, at least as regards the inner envelope, the stronger and more important of the two. As for the outer wrapper, its lack of resistance enables it to yield without difficulty when the other gives way. I cannot quite make out by what knack the Wasp contrives to detach the cap of the inner shell with such accuracy. Is it the art practised by the tailor when cutting his stuff, with mandibles taking the place of scissors? I hardly venture to admit as much: the tissue is so tough and the circle of division so precise. The mandibles are not sharp enough to cut without leaving a ragged edge; and then what geometrical certainty they would need for an operation so perfect that it might well have been performed with the compasses!