The construction, the axis of which is always nearly vertical, with an orifice opening upward, so that the fluid honey may not run out, differs a little in form, according to its basis. On a horizontal surface it rises like a little oval tower; on a vertical or slanting one it resembles half a thimble cut down its length. In this case the support—the pebble itself—completes the surrounding wall. The cell completed, the bee sets to work at once to store it. The neighbouring flowers, especially those of Genista scorpius, which in May turn the alluviums of the torrents golden, furnish sugared liquid and pollen. She comes with her crop swelled with honey, and all yellow underneath with pollen dust, and plunges head first into the cell, where for some moments one may see her work her body in a way which tells that she is disgorging honey. Her crop emptied, she comes out, but only to go in again at once—this time backwards. With her two hind feet she now frees herself from her load, of pollen by brushing herself underneath. Again she goes out, and returns head first. She must stir the materials with her mandibles for a spoon, and mix all thoroughly together. This labour of mixing is not repeated after every journey, but only from time to time, when a considerable quantity has been collected. When the cell is half full, it is stored; an egg must be laid on the honey paste, and the door has to be closed. This is all done without delay. The orifice is closed by a cover of undiluted mortar, worked from the circumference to the centre. Two days at most seem required for the whole work, unless bad weather or a cloudy day should interrupt it. Then, backing on the first cell, a second is built and stored in the same way, and a third and fourth, etc., follow, each one with honey and an egg, and closed before another is begun. Work once begun is continued until it is completed, the bee never building a new cell until the four acts required to perfect the preceding one are performed—namely, construction, provisioning, an egg, and sealing the cell. As Chalicodoma muraria always works alone on her chosen boulder, and shows great jealousy if her neighbours alight there, the number of cells clustered on one pebble is not great—usually six to ten. Are some eight larvæ her whole progeny, or will she establish a more numerous family on other boulders? The surface of the stone would allow of more cells if she had eggs for them, and the bee might build there very comfortably without hunting for another, or leaving the one to which she is attached by habit and long acquaintance. I think, therefore, that most probably all her scanty family are settled on the same stone—at all events when she builds a new abode.