Time after time the Sandy Ammophila and the Silvery Ammophila have shown me this temporary closing of the hole when the sun begins to go down and when the lateness of the hour compels the victualling to be put off till the morrow. When the dwelling had been sealed up by the Wasp, I too would postpone my observations till the next day, but only after first making a map of the ground, choosing my lines and landmarks and planting a few stalks as signposts to show me the way to the well when it was filled. If I did not come back very early in the morning, if I left the Wasp time to take advantage of the hours of bright sunshine, I invariably found the burrow finally stocked with provisions and closed. This faithfulness of memory is striking. The Wasp, delayed in her task, puts off the rest of her work to the next day. She does not spend the evening, she does not spend the night in the home which she has just dug: on the contrary, she leaves the premises altogether and goes away, after concealing the entrance with a little stone. The locality is not familiar to her; she knows it no better than any other spot, for the Ammophilæ behave like the Languedocian Sphex and lodge their families here or there, wherever they happen to roam. The Wasp was there by chance; the soil suited her; she dug her burrow; and she now goes off. Where to? Who can tell? Perhaps to the flowers not far away, where, by the last gleams of daylight, she will sip a drop of sugary liquid at the bottom of the cups, even as our miners, after toiling in their dark galleries, fly for comfort to the bottle in the evening. She goes off, to a less or greater distance, stopping at this bin and that in the flowers’ cellar. The evening, the night, the morning slip by. Still, she must return to the burrow and complete her task, she must return after the marches and countermarches of the morning hunt and the bewildering flight from flower to flower during the libations of the evening before. That the Social Wasp should return to her nest and the Social Bee to her hive does not surprise me at all: the hive and the nest are permanent residences, the way to which becomes known by long practice; but the Ammophila has no acquaintance with the locality which could help her to return to her burrow after such a long absence. Her tunnel is at a spot which she perhaps visited yesterday for the first time and which she must find again to-morrow, when she is quite out of her bearings and moreover hampered with a heavy load of game. Nevertheless, this little feat of topographical memory is performed, sometimes with a precision that left me astounded. The Wasp would walk straight to her burrow as if she had long been using all the little paths in the neighbourhood. At other times she would wander backwards and forwards and renew her search over and over again.