On a hillside near our cottage stands a log cabin, deserted and untenanted save for small creatures of the wild, which, though a favorite spot with wood–boring wasps, is an unprofitable place for study because of the difficulty of cutting out their nests without destroying property. One day in early July, however, when we were in the full fervor of hunting and longed to utilize every moment, the wasps in our garden seemed to have resolved that enjoyment and enjoyment only was their destined end and way, and became so exasperatingly idle that in disgust we turned to the cabin. For half an hour we saw nothing more exciting than a Trypoxylon immuring her victims and a Pompilus hunting spiders under the eaves, but at the end of that time Passolocus annulatus, a tiny wasp new to us, came flying quietly along and entered one of the holes with which the ends of the logs were riddled. She was carrying an aphis in her mandibles, and when this was duly stored she reappeared and flew away. She had probably just renewed her work after a spell of rest, since from this time on for nearly an hour she came back regularly every four or five minutes. She nearly always alighted on a blade of grass before going into the nest, but did not appear to be malaxing her prey. Presently another stage in the game was reached. She no longer brought aphides, but little pellets of mud with which she plastered up the opening. After she had finished this task and departed, we carefully chiseled into the log and laid bare the nest. The tunnel ran in for about three inches, and ended in three pockets which were well stocked with dead aphides, there being fifty–seven in all. The innermost cell contained a larva, and in the others were eggs, one of which hatched on the next day and one on the day following. This second one was probably laid just before the nest was sealed, giving forty hours for the egg stage; and it proved to be the healthiest of the three. The others perished in early infancy; but this one passed twelve days in eating, not only its own share of provisions, but those destined for the other members of the family as well, and then spun its cocoon.