The mother, therefore, having made her selection, takes up her stand on the stalk of the leaf and there patiently drives in her rostrum, turning it with a persistency that denotes the great importance of this thrust of the bodkin. A little wound opens, a fairly deep wound, which soon becomes a point of mortification. It is done: the sap-conduits are cut and allow only a scanty proportion to ooze through to the edge. At the injured point, the leaf gives way under the weight; it bends vertically, withers a little and soon acquires the requisite flexibility. The moment has come to work it. That bodkin-thrust represents, although much less scientifically, the prick of the hunting Hymenopteron’s sting. The latter wants for her offspring a prey now dead, now paralyzed; she knows, with the thoroughness of a consummate anatomist, at what points it behoves her to insert the sting to obtain either sudden death or merely a cessation of movement. The Rhynchites requires for her young a leaf rendered flexible ad hoc, half-alive, paralyzed in a fashion, a leaf that can easily be shaped into a scroll; she is wonderfully familiar with the little leaf-stalk, the petiole, in which the vessels that dispense the foliaceous energy are collected in a tiny bundle; and she inserts her drill there, there only and never any elsewhere. Thus, at one blow, without much trouble, she effects the ruin of the aqueduct. Where can the beaked insect have learnt her astute trade as a drier-up of wells? The leaf of the poplar is an irregular rhombus, a spear-head whose sides widen into pointed pinions. The manufacture of the scroll begins with one of those two lateral corners, the right or left indifferently. Notwithstanding the hanging posture of the leaf, which makes the upper or lower surface equally easy of access, the insect never fails to take its position on the upper side. It has its reasons, dictated by the laws of mechanics. The upper surface of the piece, which is smoother and more flexible, has to form the inside of the scroll; the lower surface, which has greater elasticity because of its powerful veins, must occupy the outside. The statics of the small-brained Weevil agree with those of the scientists. See her at work. She stands on the rolling-line, with three of her legs on the part already rolled and the three opposite on the part still free. Solidly fixed, on both sides, with her claws and tufts, she obtains a purchase with the legs on the one side, while making her effort with the legs on the other. The two halves of the machine alternate like motors, so that, at one time, the formed cylinder rolls over the free blade and, at another, the free blade moves and is laid upon the scroll already made.