This was our first specimen of marginatus, and a month passed before we met another. It was while watching some Bembecidæ that we saw the pretty little orange–spotted worker dragging a small Thomisid across their nesting–ground. The spider was so small that she held it in her mandibles well above the ground, and we speak of her as dragging it only because she walked backward and acted as though she were obliged to exert herself. Quite often the spiders taken by this species are too large to be carried, and then it is necessary to drag them; this habit is so ingrained that when it would be much more convenient to go straight ahead they stick to the ancient custom, and seem unable to move in any other way. This little wasp was in a frantic hurry, running backward into the Bembex holes and then scrambling out again, until she had crossed the field and had turned to one side, having gone, since we first saw her, about fifteen feet. Here she dropped the spider and began to skim over the ground—it could not be called running and yet it was not flying—until she found a circular hole in the black earth, which looked as if it ran vertically downward. At the time we thought that this was a nest that she had made for herself, but we afterward concluded that it had been excavated by some other creature, that she had found it and determined to make use of it, and that she was bringing her prey to the spot with that end in view. Without entering she rushed back to the spider, but after carrying it a few inches, dropped it and ran to take another look at the nest. By this time, however, she was too much excited to know what she was about, and for five minutes she scurried over the ground without finding it. During this time she picked up the spider four times, carried it a little way, and then dropped it. The last time she carried it to the edge of the grass and stowed it there, this being her first attempt at concealment. She now found the hole again and brought the spider nearly to it, but by this time she was perfectly beside herself. The spider was seized again and again, only to be dropped the next second, while the wasp rushed back and forth between it and the hole. In time this method of procedure brought it close to the nest, but it was carried around the edge once or twice even then. At last, accidentally as it seemed, it fell in, when the wasp quickly ran in also and pulled it down. For half an hour she remained inside, and when she came out we caught her to make sure of her identity. As we set her free immediately we expected her to go to work at covering her nest, but in this we were disappointed, for she did not return. We left the place undisturbed from the thirteenth to the fifteenth of August, when we dug up the nest. The Thomisid was there, but we could find neither egg nor larva. The spider was alive, as was shown by a quivering of the legs. This quivering grew fainter and fainter, until upon the nineteenth it was