The nests of quinquenotatus vary considerably according to the kind of soil in which they are made, the firm clay of the garden giving a result quite different from the fine dry earth of the island, in which they are usually much larger, and scarcely to be distinguished from the holes of Bembex spinolæ. In both localities, however, the nest consisted of a short tunnel, running obliquely downward, with a slight enlargement at the end, but with no change in the direction of the gallery. [Illustration: NEST OF P. QUINQUENOTATUS] In the loose sand of a steep hillside we found that the wasps had a different method. Their tunnels in this place filled up nearly as fast as they could dig them, and when they had reached a depth of half an inch they turned off at a right angle, and excavated in an entirely new direction. They probably derived some advantage from this variation, for we saw four in succession follow the same plan, which certainly appeared to be an intelligent adaptation of means to ends. We once saw a wasp of this species digging her nest on the Bembex field. When finished it was a large hole which could not have been distinguished from those of spinolæ, which were open all about, the weather being bright and sunny. She flew off, and soon reappeared with her spider, which was dropped three feet away while she ran to make sure that all was right; and now followed something that we had never seen before—she could not find her nest. She flew, she ran, she scurried here and there, but she had utterly lost track of it. She approached it several times, but there are no landmarks on the Bembex field. We have often wondered how they find their own places. After five minutes our wasp flew back to look at her spider, and then returned to her search. She now began to run into the Bembex holes, but soon came out again, even when not chased out by the proprietor. Suddenly it seemed to strike her that this was going to be a prolonged affair, and that her treasure was exposed to danger; and hurrying back she dragged it into the grass at the edge of the field, where it was hidden. Again she resumed the hunt, flying wildly now all over the field, running into wrong holes and even kicking out earth as though she thought of appropriating them, but soon passing on. Once more she became anxious about the spider, and carrying it up on to a plant suspended it there. Now she seemed determined to take possession of every hole that she went into, digging quite persistently in each, but then giving it up. On one that seemed to be unoccupied she labored at enlarging the entrance, until we thought that she had mistaken it for her own, or at least had determined to use it. At last, however, she made up her mind that all further search was hopeless and that she must start afresh; and forty minutes from the time that we saw her first she began a new nest close to the spider, as though she would run no more risks.