But the favourite spot is the great fountain in the village, where the people come to water their mules. Here there is a constant sheet of black mud which neither the hottest sunshine nor the strongest wind can dry. [[77]]This bed of mire is very unpleasant for the passers-by, but the Pelopæus loves to gather her pellets here, amid the hoofs of the mules.
Unlike some builders in clay, such as the Mason-bees, the Wasp does not improve the mud to make it into mortar, but uses it just as it is. Consequently her nests are flimsy work, absolutely unfitted to stand the changes and chances of the open air. A drop of water laid upon their surface softens the spot touched and reduces it to mud again, while a sprinkling equal to an average shower turns it to pap. They are nothing but dried slime, and become slime again as soon as they are wetted.
It is plain, then, that even if the young Pelopæus were not so chilly by nature, a shelter is indispensable for the nests, which would go to pieces at the first shower of rain. That is why this Wasp is so fond of human dwellings, and especially of the chimney.
Before receiving its final coating, which covers up the details of the building, the nest has a certain beauty of its own. It consists of a cluster of cells, sometimes arranged side by side in a row—which makes it look rather like a mouth-organ—but more often grouped in layers placed one above the other. I have sometimes counted as many as fifteen cells; some nests contain only ten; others are reduced to three or four, or even only one.
In shape the cells are not far from cylinders, slightly [[78]]larger at the mouth than at the base. They are a little more than an inch long, and about half an inch wide. Their delicate surface is carefully polished, and shows a series of string-like projections, running cross-wise, not unlike the twisted cords of some kinds of gold-lace. Each of these strings is a layer of the building; it comes from the clod of mud used for the coping of the part already built. By counting them you can tell how many journeys the Wasp has made in the course of her work. There are usually between fifteen and twenty. For one cell, therefore, the industrious builder fetches materials something like twenty times.
The mouth of the cells is, of course, always turned upwards. A pot cannot hold its contents if it be upside down. And the Wasp’s cell is nothing but a pot intended to hold the store of food, a pile of small Spiders.
The cells—built one by one, stuffed full of Spiders, and closed as the eggs are laid—preserve their pretty appearance until the cluster is considered large enough. Then, to strengthen her work, the Wasp covers the whole with a casing, as a protection and defence. She lays on the plaster without stint and without art, giving it none of the delicate finishing-touches which she lavishes on the cells. The mud is applied just as it is brought, and merely spread with a few careless strokes. The beauties of the building all disappear under this ugly [[79]]husk. In this final state the nest is like a great splash of mud, flung against the wall by accident.