Chalicodoma sicula has a yet greater variety of choice. Her favourite position is under a tile projecting from the edge of a roof. There is scarcely a little dwelling in the fields that does not thus shelter her nests. There, every spring, she establishes populous colonies, whose masonry, transmitted from one generation to another, and yearly enlarged, finally covers a very considerable surface. I have seen such a one under the tiles of a shed, which spread over five or six square yards. When the colony were hard at work, their number and humming fairly made one dizzy. The underpart of a balcony pleases them equally, or the frame of an unused window,—above all, if closed by a sun-shutter, which offers a free passage. But these are great meeting-places, where labour, each for herself, hundreds and thousands of workers. If alone, which not seldom occurs, Chalicodoma sicula establishes herself in the first little spot she can find, so long as it has a solid basis and heat. As for the nature of this basis it matters little. I have seen nests built on bare stones and brick, on a shutter, and even on the glass panes in a shed. One thing only does not suit the bee—namely, the stucco of our houses. Prudent, like her retainer C. muraria, she would fear ruin to her cells did she entrust them to a support which might fall. Finally, for reasons which I cannot yet satisfactorily explain, C. sicula often entirely changes her manner of building, turning her heavy mortar dwelling, which seems to require a rock to support it, into an aerial one, hung to a bough. A bush in a hedge,—no matter what—hawthorn, pomegranate, or Paliurus,—offers a support, usually about the height of a man, Ilex and elm give a greater height. The bee chooses in some thicket a bough about as thick as a straw, and constructs her edifice on this narrow base with the same mortar which would be used under a balcony or the projecting edge of a roof. When finished, the nest is a ball of earth, traversed literally by the bough. If made by a single insect it is the size of an apricot, and of a fist if several have worked at it; but this seldom occurs. Both species use the same materials, a calcareous clay, mixed with a little sand and kneaded with the mason’s own saliva. Damp spots which would facilitate labour and spare saliva to mix mortar are disdained by the Chalicodoma, which refuses fresh earth for building, just as our builders refuse old plaster and lime. Such materials when soaked with humidity would not hold properly. What is needed is a dry powder, which readily absorbs the disgorged saliva, and forms with the albuminous principles of this liquid a kind of Roman cement, hardening quickly,—something like what we obtain with quicklime and white of egg.