All comb when first formed is clear and transparent. The fact that it is often dark and opaque implies that it has been long used as brood-comb, and the opacity is due to the innumerable thin cocoons which line the cells. These may be separated by dissolving the wax; which may be done by putting it in boiling alcohol. Such comb need not be discarded, for if composed of worker-cells, it is still very valuable for breeding purposes, and should not be destroyed till the cells are too small for longer service, which, will not occur till after many years of use. The function, then, of the wax, is to make comb, and caps for the honey-cells, and, combined with pollen, to form queen-cells (Fig. 28, _d_) and caps for the brood-cells. (See Appendix, page 301). POLLEN, OR BEE-BREAD. An ancient Greek author states that in Hymettus the bees tied little pebbles to their legs to hold them down. This fanciful conjecture probably arose from seeing the pollen balls on the bees' legs. Even such scientists as Réaumur, Bonnet, Swammerdam, and many apiarists of the last century, thought they saw in these pollen-balls the source of wax. But Huber, John Hunter, Duchet, Wildman, and others, noticed the presence and function of the wax-pellets already described, and were aware that the pollen served a different purpose. This substance, like honey, is not secreted, nor manufactured by the bees, only collected. The bees usually obtain it from the stamens of flowers. But if they gain access to flour when there is no bloom, they will take this in lieu of pollen, in which case the former term used above becomes a misnomer, though usually the bee-bread consists almost wholly of pollen. As already intimated, the pollen is conveyed in the pollen-baskets (Fig. 22, _p_) of the posterior legs, to which it is conveyed by the other legs, and compressed into little oval masses. The motions in this conveyance are exceedingly rapid. The bees not infrequently come to the hives, not only with replete pollen-baskets, but with their whole under surface thoroughly dusted. Dissection will also show that the same bee may have her sucking stomach distended with honey. Thus the bees make the most of their opportunities. It is a curious fact, noticed even by Aristotle, that the bees, during any trip, gather only a single kind of pollen, or only gather from one species of bloom. Hence, while different bees may have different colors of pollen, the pellets of bee-bread on any single bee will be uniform in color throughout. It is possible that the material is more easily collected and compacted when homogeneous.