Third experiment.—To know all and nothing, according as the conditions are normal or otherwise, is the strange antithesis presented by the insect. Other examples drawn from the Sphegidæ will confirm us in this proposition. Sphex albisecta attacks middle-sized Acridians, the various species scattered in the neighbourhood of her burrow all furnishing a tribute. From the abundance of these Acrididæ the chase is carried on near at hand. When the vertical well-like burrow is ready, the Sphex merely flies over the ground near, and espies an Acridian feeding in the sunshine. To pounce and sting while it struggles is done in a moment. After some fluttering of the wings, which unfold like carmine or azure fans, some moving of feet up and down, the victim becomes motionless. Next it must be got home by the Sphex on foot. She performs this toilsome operation as do her kindred, dragging her game between her feet, and holding one of the antennæ in her mandibles. If a grass thicket has to be traversed, she hops and flutters from blade to blade, keeping firm hold of her prey. When within a few feet of her dwelling she executes the same manœuvre as does S. occitanica, but without attaching the same importance to it, for sometimes she neglects it. The game is left on the road, and though no apparent danger threatens the dwelling, she hurries toward its mouth, and puts in her head repeatedly, or even partly enters, then returns to the Acridian, brings it nearer, and again leaves it to revisit her burrow, and so on several times, always with eager haste. These repeated visits have sometimes annoying results. The victim, rashly abandoned on a slope, rolls to the bottom, and when the Sphex returns and does not find it where she left it, she must hunt for it, sometimes in vain. If found, there will be a difficult climb, which, however, does not prevent her leaving it once more on the perilous slope. The first of these repeated visits to her cell is easily explained. Before bringing her heavy load she is anxious to make sure that the entrance is clear, and that nothing will hinder her carrying in the prey. But what is the use of her other visits, repeated so speedily one after another? Are the Sphex’s ideas so unstable that she forgets the one just made, and hurries back a moment later, only to forget that she has done so, and so on? It would indeed be a slippery memory where impressions vanished as soon as made. Let us leave this too obscure question.