It was on the last day of July that, as we were walking through the bean field, we saw a cloud of fine dust which came spurting up out of the ground like water in a fountain. By watching intently we saw that the cause of the commotion was the rapid action of the legs of some little creature that was almost hidden in the earth, and this proved to be our first example of P. quinquenotatus. She was working away as furiously as though she had studied the poets and knew her _carpe diem_ by heart. Faster and faster went the slender little legs; higher and higher rose the jet of dust above her. Then suddenly there was a pause. The burrower had met with some obstacle. A moment more and she came backing out of the hole, her feet slipping on its crumbling edges. In her mandibles she carried a pebble, which was taken to a distance of four or five inches. Then, moving quickly, she swept away the dust that had accumulated near the mouth of the nest, reëntered the hole, and resumed the labor of excavation. We thought that the rate at which she worked was too violent to be kept up very long; and sure enough, before ten minutes had passed the nest was deep enough for her purposes, and we afterward learned, to our chagrin, that it was too deep for ours. The wasp came out, circled round the spot three or four times, and then flew off like a hurricane. Never have we seen a creature so fiery, tempestuous, cyclonic. Before we knew her proper title we took to calling her the tornado wasp, and by that name we shall always think of her. [Illustration: POMPILUS QUINQUENOTATUS] Her flight was too rapid to follow, but in a minute we saw her returning. She was carrying a spider, a good–sized specimen of Epeira strix, which she had evidently deposited somewhere in the neighborhood before beginning to dig. Alighting near by, she left the spider lying on the ground, while she ran to her nest and kicked out a little more earth. Then seizing it by one leg, she dragged it, going backward herself, into the nest. She remained hidden for about two minutes, then reappeared, and, seeming to be in as great a hurry as ever, filled the hole with dirt. To disguise the spot and render it indistinguishable from the rest of the field was her next care. Hither and thither she rushed, now bringing little pellets of earth and placing them above the nest, now sweeping away the loose dust which might suggest the presence of the _cache_, and now tugging frantically at a stone which she wanted to place over the hidden treasure, but which was too deeply embedded in the earth to yield to her efforts. She did her work faithfully, although with such eager haste that all was completed at the end of twenty minutes from the time we saw her first. So well was the place hidden that it was only by careful orientation that we could be certain of its exact locality.