OCR Text |
Show 200 INSTINCT. [Cu.u. VII with fitting tools and 1neasures, ·would find it very di:ffi~ cult to 1nake cells of wax of the true form, though this is p~rfectly effected by a ~ro,vd of bees working in a dark hive. Grant whatever Instincts you please and it seems at first quite inconceivable how they cad m_ake all the necessary angles and planes, or even perceive when they are corr~ctly made. But the difficulty is not nearly so great as It at first appears : all this beautiful work can b~ shown, I think, to follow from a few very simple instincts. I was led to investigate this subject by Mr. Waterhouse, wh? has shown that the form of the cell stands in close r_elatlo~ to the presence of adjoining cells ; and the follo:w1ng_ VIew 1_nay, perha:ps, be considered only as a rr;odrficatlon of ~:ns theory. Let us look to the great prinmple of gradation, and see whether Nature does not reve~ l to us her method of work. At one end of a short senes we have humble-bees, which use their old cocoons to hold hon_ey s~Inetime~ adding to them short tubes of wax, and hkewise rnalnng separate and very irregular rounded cells of wax. At the other end of the series we have the cell~ of the hive-be~, placed in a double layer: each cell, as IS well known, IS an hexaO'onal prism with the basa~ edges of its six sides bevelled ~o as to join' on to a py~an1Id, forined of three rhombs. These rho1nbs have certain ang:les, and the three which forn1 the pyramidal base of a s~ngle cell on one side of the comb, enter into the co_mp~sitlon of the ba~es of three adjoining cells on the O_Pposite Side. In the s~nes between the extreme perfection of the cells of the hive-bee and the simplicity of those o_f the humble-?ee, 've have the cells of the Mexican MehJ? ona domestwa, carefu~ly described and figured by Pierre Huber. The Mehpona itself is intermediate in structure. between the hive and humble bee, but more nearly related to ~he Iatter: it . forms a nearly regular waxen comb o~ cyhn~r~cal eells, 1n which the young are hatc~ed, and, In add1tlon, some large cells of wax for holding honey. The~e 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· CHAP. VII.] CELLS OF THE HIVE-BEE. 201 these cells are always made at that degree of nearness to each other, that they would have intersected or broken into each other, if the spheres had been con1pleted; but this is never pern1itted, the bees building perfectly flat walls of wax between the spheres whieh thus tend to inte: rsect. Hence each cell consists of an outer spherical portion and of two, three, or more perfectly flat surfaces, according as the cell adjoins two, three, or more other cells. When one cell co1nes into contact with three other cells, which, from the spheres being nearly of the same size, is very frequently and necessarily the case, the three flat surfaces are united into a pyramid ; and this pyramid, as I-Inber has rmnarked, is manifestly a gross imitation of the three-sided pyramidal basis of the cell of the hive-bee. As in the cells of the hive-bee, so here, the three plane surfaces in any one cell necessarily enter into the construction of three adjoining cells. It is obvious that tho ~1elipona saves vvax by this Inanner of building; for the flat walls between the adjoining cells arc not double, but are of the same thickness as the outer spherical portions, and yet each flat portion forn1s a part of two cells. Reflecting on this case, it occurred to me that if the Melipona had made its spheres at some given distance fron1 each other, and had made them of equal sizes and had arranged them symmetrically in a double layer, the resulting structure would probably have been as perfect as the comb of the hive-bee. Accordingly I wrote to Professor Miller, of Oa1nbridge, and this geometer has kindly read over the following statement, drawn up fro1n his infonnation, and tells me that it is strictly correct:- If a number of equal spheres be described with their centres placed in two parallel layers ; with the centre of each sphere at the distance of radius x ,Y 2, or radius x 1·41421 (or ~t some lesser distance), from the centres of the six surrounding spheres in the same layer; and at the same distance from the centres of the adjoining spheres in the other and parallel layer; then, if planes of intersection between the several spheres in both layers be formed, there will result a double layer of hexagonal prisms united together by pyramidal bases formed of three 9* |