CREATION BY EVOLUTION
the hairs of the under surface of the body. To place this pollen in the cell the bee enters backward and, with the aid of its hind-legs, brushes and scrapes and combs the pollen off from the under surface of its body so that it falls into the cell. This is a distinct advance on what we had at the beginning of our series, where the pollen is swallowed and brought up again. The pollen and honey are, however, not kept separate, but are worked up by the jaws of the bee into a paste, on which the egg is laid, and the cell is then closed with cement. The work of building this cell takes about two days, and after it is finished the bee will begin to make a second cell close to the first, and will continue its work until it has made eight or nine cells, when it places a thick, dome-like layer of mortar over the whole series. The result is a nest about the size of half an orange. The larvae live in these nests for months; they do not pass through their life-history so rapidly as the honey-bee.
An equally ingenious insect is the carder bee, which has developed the habit of making nests of wool or cotton, obtained from plants that grow in the neighbourhood. This bee is referred to by Gilbert White in his “Natural History of Selborne.” The male, like that of the honey-bee, is conspicuously larger than the female. These carder bees build their nests in any hollow, such as a cavity in wood or a deserted nest of other bees, or in an empty snail shell. In order to retain in the cell the fluid mixture of pollen and honey they line the cell with a thin cement. A few allied species form their cells of resin instead of wool or cotton.
The last of the solitary bees we shall consider are the carpenter-bees. These are big, burly black or bluish-black bees. They have powerful jaws, with which they carve their way into dried wood. They avoid living timber, but they will bore a hole into a beam or a rafter, and this hole will lead
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