Besides honey and bee-bread two other substances are found in beehives. These are propolis and beeswax. The former is a kind of sticky resin collected for the most part from coniferous trees. This is used as mortar in building, &c. It adheres so strongly to the legs of the bee which has gathered it, that it can only be detached by the help of comrades. For this purpose the loaded bee presents her legs to her fellow-workers, who clean it off with their jaws, and while it is still ductile, apply it round the inside of the hive. According to Huber, who made this observation, the propolis is applied also to the insides of the cells. The workers first planed the surfaces with their mandibles, and one of them then pulled out a thread of propolis from the heap deposited by the carrier bees, severed it by a sudden throwing back of the head, and returned with it to the cell which it had previously been planing. It then laid the thread between the two walls which it had planed; but, proving too long, a portion of the thread was bitten off. The properly measured portion was then forced into the angle of the cell by the fore-feet and mandibles. The thread, now converted into a narrow ribbon, was next found to be too broad. It was therefore gnawed down to the proper width. Other bees then completed the work which this one had begun, till all the walls of the cells were framed with bands of propolis. The object of the propolis here seems to be that of giving strength to the cells. The wax is a secretion which proceeds from between the segments of the abdomen. Having ingested a large meal of honey, the bees hang in a thick cluster from the top of their hive in order to secrete the wax. When it begins to exude, the bees, assisted by their companions, rub it off into heaps, and when a sufficient quantity of the material has been thus collected, the work begins of building the cells. As the cells are used both for storing food and rearing young, I shall consider them later on. Now we have to pass to the labours incidental to propagation.