owner of the prey was disturbed and dashed at her, driving her away again and again, but she flew only a short distance and was soon back, always creeping nearer and nearer to the spider. We, too, were watching with closest attention, but our desire was to see the speedy homecoming of Pompilus and to learn whether she cut off the legs of her victim; and so, interesting as was the contest between the wasp and the wasp–inquiline, we decided to interfere and remove the intruder. This was very easily accomplished, since the little insect was so intent upon following the spider that she was oblivious to our presence, and allowed us to place a bottle over her as she stood eagerly looking for a chance to advance. Her removal gave great relief to the other wasp, as was manifested by an entire change of manner. Before, she had been constantly on the lookout, moving only with the greatest circumspection, but now she relaxed her vigilance. With the Ceropales in our vial we, too, felt relieved, and now the path of discovery seemed clear before us; but scarcely had things assumed their old status when a second enemy, a much larger and bolder Ceropales, threw both the Pompilus and ourselves into consternation. Again we took the side of our wasp and drove the other one off, but only to see it return a few moments later. The Pompilus now flew at it in a most gallant fashion and pursued it far afield, but when she came back the enemy was but a few seconds behind her. Here we again interposed and removed the second Ceropales from the field of action.