P. fuscipennis rarely circles about when leaving a place; this is unfortunate, since her sense of locality seems to be particularly weak. She nearly always has to hunt for the plant upon which she has placed her spider, and always loses track of her nest when she tries to bring the spider to it. We once caught her as she was carrying her spider, and then released her on the same spot; but she became so much confused that without our assistance she would never have found it again. Our acquaintance with Pompilus marginatus began in the middle of July. She is a small creature, only half an inch long, and is dressed in black, with a bright orange spot on each side of the anterior part of the abdomen. We were watching the pretty little Diodonti, as they filled their holes with aphides, when we saw her going backward, dragging along a medium–sized spider. Soon she came to an onion flower that was lying on the ground. Here she stopped and, after a moment’s hesitation, drew her prey in among the blossoms of the cluster so that it was hidden from view. It was not long before she came out and began to fly about near the ground, frequently alighting to poke her head into cracks and to run again and again into little chance holes. Never did an insect behave in a more demented manner, and although there may have been a method in her madness it was difficult to discover it. No hole nor cranny pleased her, and back she flew to the onion to see whether her booty were safe. For fifteen minutes she ran and flew now here, now there, hurry and anxiety in every movement, returning frequently to reassure herself about the spider. Several times she entered a hole at the base of a weed, not a made nest, but an accidental crevice; and this spot was at length chosen either as a temporary or a final resting place for her spider, since she dragged it from the onion and deposited it here. We tried to capture the wasp; but having failed in this, we dug out the spider. It was three inches down, the hole being deeper than it looked from the outside. There was no egg upon it. Evidently the work had not been finished, for the restless creature returned fifteen times within an hour to the broken nest, either for the purpose of laying her egg or to remove the spider to another resting–place on her homeward way. [Illustration: POMPILUS MARGINATUS]