The wasp attacked at once, but was rudely repulsed, the caterpillar rolling and unrolling itself rapidly and with the most violent contortions of the whole body. Again and again its adversary descended, but failed to gain a hold. The caterpillar, in its struggles, flung itself here and there over the ground, and had there been any grass or other covering near by it might have reached a place of partial safety; but there was no shelter within reach, and at the fifth attack the wasp succeeded in alighting over it, near the anterior end, and in grasping its body firmly in her mandibles. Standing high on her long legs and disregarding the continued struggles of her victim, she lifted it from the ground, curved the end of her abdomen under its body, and darted her sting between the third and fourth segments. From this instant there was a complete cessation of movement on the part of the unfortunate caterpillar. Limp and helpless, it could offer no further opposition to the will of its conqueror. For some moments the wasp remained motionless, and then, withdrawing her sting, she plunged it successively between the third and the second, and between the second and the first segments. The caterpillar was now left lying on the ground. For a moment the wasp circled above it, and then, descending, seized it again, further back this time, and with great deliberation and nicety of action gave it four more stings, beginning between the ninth and tenth segments and progressing backward. Urnaria, probably feeling—as we certainly did—a reaction from the strain of the last few minutes, and a relief at the completion of her task, now rested from her labors. Alighting on the ground close by, she proceeded to smooth her body with her long hind legs, standing, in the mean time, almost on her head, with her abdomen directed upward. She then gave her face a thorough washing and rubbing with her first legs, and not until she had made a complete and satisfactory toilet did she return to the caterpillar. We saw Ammophila capture her prey only three times during the whole summer; but from these observations and from the condition of her caterpillars taken at various times from nests, her method seems to be wonderfully close to that of hirsuta, with just about the same amount of variation in different individuals.