It was eleven o’clock when she flew away. At half past twelve she reappeared, coming from the direction of the woods, opened her nest, and took out a few more pellets. Then she flew to a bush which grew against the fence, three feet away, and following her quickly we saw an immense green caterpillar placed high up on a branch. It must have taken both strength and perseverance to lift this heavy weight so far from the ground. She seized it at once and carried it down, not flying, as these wasps sometimes do when they are descending with a burden, and then dragged it into her nest, where it fitted rather tightly. This nest was so shallow and so obliquely directed that the caterpillar was plainly visible after it had been taken in. After she had laid her egg she crawled out, getting past the caterpillar with some difficulty, and closed the nest. There was certainly no room for any further store of provisions, and from the size of the caterpillar we judged that it would furnish sufficient nourishment even for the offspring of this wasp. We were, therefore, not surprised, upon opening the nest two days later, to find that nothing more had been brought. We have said that the wasp larvæ spend from six days to two weeks in eating. To be more exact, all that we watched, with the exception of the one which developed from the egg of this big creature, ate from six to eight days and then spun their cocoons; but this one seemed determined to reach the size of its mother, and ate continuously for fourteen days. Of course long before this time had expired the remnant of the caterpillar had become a dry, dark–colored mass which looked little likely to tempt the appetite, but the great larva ate away with unabated relish, gradually acquiring the color and almost the thickness of the caterpillar it had destroyed. Ammophila polita, which we have never seen in the country, is very common in the sandy fields to the south of Milwaukee. On the tenth of September, in bright clear weather, we found half a dozen individuals working within a few rods of each other, their method being similar to that of A. yarrowii, described by Dr. Williston, and having an especial interest, as it shows a transition stage between the wasps that provide the store of food all at once and those that feed their young all through the larval period. Urnaria rarely flies with her prey; but this wasp, although her caterpillars, are not very much smaller, and she herself is no larger, carries her booty lightly on the wing, alighting only occasionally to run a few steps. She has to do more work than urnaria, taking five or six caterpillars instead of two, and this method of progression has the advantage of rapidity.