This nest was successfully completed, and the spider was stored away without further misadventure. The egg of quinquenotatus can be but lightly attached to the spider, for only once, out of many attempts, did we succeed in getting it out without displacing it. In this case three days elapsed before it hatched. The larva ate for a day or two, but then pined away and died. Another nest was opened on the tenth day after the egg was laid, and in this the spider had been entirely eaten and the larva was just spinning its cocoon; so that the larval stage probably occupies about a week. A summary of our notes shows a very wide variation in the condition of the spiders stored by this wasp. Out of eleven that were stung three were killed at once, two lived four days, one five, one eleven, one twenty–three, one twenty–five, one thirty–one, and one at least forty days and probably longer. We look back with much pleasure upon our acquaintance with this gay, excitable little wasp. She was so full of breezy energy that it was always delightful to meet her, and she showed so wide a variation in individual character that we seldom watched her without learning something new. Pompilus fuscipennis, a little smaller than P. quinquenotatus, is black, with the red girdle that appears so frequently among the solitary wasps. The first time that we ever saw this wasp she was running rapidly backward over the bare ground, the brilliant red of her body flashing in the sunlight as she dragged along a little spider of the genus Thomisus. Presently she carried it up on to a leaf and began to bite at it, but being disturbed by an ant, hurried on with a much agitated manner. Soon she stopped again and resumed her attack, biting savagely at the legs near their junction with the body, and now, looking closely, we saw that two of them had been completely cut off. While occupied in this way the wasp was evidently intensely excited. She lay on one side with the abdomen bent under, turning the spider over and over as she worked. After a time she carried it onward to the potato–field, where the plants afforded some shelter, and placing it upon a leaf, well above the ground, began to dig near by. She worked almost entirely with her mandibles, lying sometimes on her side and sometimes on her back as she cut away the earth, which was pushed out with the end of her abdomen. When she had worked for ten minutes and had gone in the length of her body, she picked up the spider and rapidly made off with it, several times rising on her wings and flying backward for a few inches. A little further along she again deposited it on a leaf and began to dig in a fresh place. At the end of twenty minutes the nest was ready, but in bringing the spider she missed her direction and carried it to one side. Dropping it on the ground, she began to hunt about for her hole, but was distracted with excitement and ran so far afield that we feared she would never find it. At last,