If the quest is greatly prolonged, the prey, which is a troublesome burden when you are in a hurry to find your home, is laid down in some high place, on a cluster of thyme or a tuft of grass, where it will be well in sight presently, when wanted. Thus eased, the Ammophila resumes her active search. I made a pencil-sketch, as she moved about, of the tracks followed. The result was a medley of tangled lines, with sudden bends and turns, branches in and branches out, windings and repeated intersections—in short, a regular labyrinth whose complicated maze was an ocular demonstration of the perplexity of the lost one. When the well has been found and the slab removed, the Wasp has to come back to the caterpillar, which is not always done without some groping about, in cases where her wanderings to and fro have been very numerous. Though she left her prey easily visible, the Wasp appears to foresee the difficulty of finding it again when the moment comes to drag it home. At least, if the search is unduly prolonged, you see her suddenly interrupt her exploration of the ground and return to her caterpillar, which she feels and nibbles at for a moment, as though to make sure that it is really her own game, her property. Then she hurries back again to the field of search, which she leaves a second time, if need be, and a third, in order to inspect the prey. I am not at all sure that these repeated visits of the Wasp to the caterpillar are not a means of refreshing her memory of the place where she left it. This is what happens in exceedingly complicated cases; but as a rule the Wasp goes back quite easily to the well dug the day before on the spot to which chance has taken her. The vagabond’s guide is her topographical memory, whose marvellous feats I shall have to tell later. As for me, in order to return next day to the well hidden under the lid of the little flat stone, I dared not trust to my unaided memory: I needed notes, sketches, lines of latitude and longitude, landmarks—in short, all the minutiæ of geometry.