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Show 232 INSTINCT. CHAP. VII. of a si. ngle cell, or the extreme margi· n of the circuinfe.r - enti.a l n.m 0 f a growi.n g com b' un ri"th an• extr•e mely thin layer of melted vermilion wa~; and ~ Invanably found that the colour was most delicately diffused by t~e be~s -as delicately as a painter could have. done With hJS brush-by atoms of the coloured wax having been taken from the spot on which it had been placed, an~ worked into the growing edges of the cells all round. The work f nstruction seems to be a sort of balance struck 0 00 di h between many bees, all instinctively stan ng ~t t e same relative distance from each other, all trying to sweep equal spheres, and then building up, or leaving ungnawed, the planes of intersection between th.ese spheres. It was really curious to note in cases of difficulty, as when two pieces of comb met at an angl~, ho.w often the bees would entirely pull down and rebuild In different ways the same cell, sometimes recurring to a shape which they had at first rejected. When bees have a place on which they can stand in their proper positions for working,-for instance, on a slip of wood, placed directly under the middle of ~ comb growing downwards so that the comb has to be built over one face of the slip-in this case the bees can lay the foundations of one wall of a new hexagon, in its strictly proper place, projecting beyond the other completed cells. It suffices that the bees should be enabled to stand at their proper relative distances from each other and from the walls of the last completed cells, and then, by striking imaginary spheres, they can build up a wall intermediate between two adjoining spheres; but, as far as I have seen, they never gnaw away and finish off the angles of a cell till a large part both of that cell ~nd ?f the adjoining cells has been built. This capacity m bees of laying down under certain circums~ances a rough wall in its proper place between two JUSt-com- CHAP. VII. CELLS OF THE HIVE-BEE. 233 menced cells, is important, as it bears on a fact, which seems at first quite subversive of the foregoing theory; namely, that the cells on the extreme margin of wasp-combs are sometimes strictly hexagonal; but I have not space here to enter on this subject. Nor does there seem to me any great difficulty in a single insect (as in the case of a queen-wasp) making hexagonal cells, if she work alternately on the inside and outside of two or three cells commenced at the same time, always standing at the proper relative distance from the parts of the cells just begun, sweeping spheres or cylinders, and building up intermediate planes. It is even conceivable that an insect might, by fixing on a point at which to commence a cell, and then moving outside, first to one point, and then to five other points, at the proper relative distances from the central point and from each other, strilre the planes of intersection, and so make an isolated hexagon : but I am not aware that any such case has been observed; nor would any good be derived from a single hexagon being built, as in its construction more materials would be required than for a cylinder. As natural selection acts only by the accumulation of slight modifications of structure or instinct, each profitable to the individual under its conditions of life, it may reasonably be asked, how a long and graduated succession of modified architectural instincts, all tending towards the present perfect plan of construction, could have profited the progenitors of the hive-bee? I think the answer is not difficult : it is known that bees are often hard pressed to get sufficient nectar ; and I am informed by Mr. Tegetmeier that it has been experimentally found that no less than from twelve to fifteen pounds of dry sugar are consumed by a hive of bees for the secretion of each pound of wax; so that a prodigious quantity of fluid nectar must be collected and consumed by the bees in a hive for I I |