Seite - 280 - in The Origin of Species

280 ORIGIN OF SPECIES that a skilful workman with fitting tools and measures, would find it very difficult to make cells of wax of the true form, though this is effected by a crowd of bees working in a dark hive. Granting whatever instincts you please, it seems at first quite inconceivable how they can make all the necessary angles and planes, or even perceive when they are correctly made. But the difficulty is not nearly so great as it at first appears: all this beautiful work can be shown, I think, to follow from a few simple instincts. I was led to investigate this subject by Mr. Waterhouse, who has shown that the form of the ceil stands in close relation to the presence of adjoining cells; and the follow- ing view may, perhaps, be considered only as a modification of his theory. Let us look to the great principle of grada- tion, and see whether Nature does not reveal to us her method of work. At one end of a short series we have humble-bees, which use their old cocoons to hold honey, sometimes adding to them short tubes of wax, and likewise making separate and very irregular rounded cells of wax. At the other end of the series we have the cells of the hive- bee, placed in a double layer: each cell, as is well known, is an hexagonal prism, with the basal edges of its six sides bevelled so as to join an inverted pyramid, of three rhombs. These rhombs have certain angles, and the three which form the pyramidal base of a single cell on one side of the comb enter into the composition of the bases of three adjoining cells on the opposite side. In the series between the extreme perfection of the cells of the hive-bee and the simplicity of those of the humble-bee we have the cells of the Mexican Melipona domestica, carefully described and figured by Pierre Hwber. The Melipona itself is intermediate in structure be- tween the hive and humble-bee, but more nearly related to the latter ; it forms a nearly regular waxen comb of cylin- drical cells, in which the young are hatched, and, in addi- tion, some large cells of wax for holding honey. These latter cells are nearly spherical and of nearly equal sizes, and are aggregated into an irregular mass. But the important point to notice is, that these cells are always made at that degree of nearness to each other that they would have inter- sected or broken into each other if the spheres had been