OiiAP. VII. CELL-MAKING INSTINCT. 217 



culty is not nearly so great as it at first appears : all this beau- 

 tiful work can be shown, I think, to follow from a few simple 

 instincts. 



I was led to investigate this subject by INIr. Waterhoiisc, 

 who hasshown that the form of the cell stands in close relation 

 to the presence of adjoining cells ; and the following view may, 

 perhaps, be considered only as a modilicalion of his theory : 

 let us look to the great priucijile of gradation, and see Avhether 

 Nature does not reveal to us licr method of woik. At one end 

 of a .short series we have huiuble-l)ees, which use their old 

 cocoons to hold honey, soinctiTucs adding to them short tubes 

 of wax, and liUewi.s<; making separate and very iiTCgular rounded 

 cells of wax. At the other end (if the series Ave have the cells 

 of the hive-bee, jilaced in a doiil)le la^-er: each cell, as is well 

 known, is an hexagonal prism, with the basal edges of its six 

 sides bevelled so as to lit on to a pj-ramid, formed 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 ad- 

 joining cells on the opposite side. In the series between the 

 extreme perfection of the cells of the hive-bee and the simpli- 

 city of those of the humble-bee, we have the cells of the Mexi- 

 can ^lelipona domestica, carefully described and figured by 

 Pierre Iluber. llie I\Ielipona itself is intermediate in structure 

 between the hive and humble bee, but more nearly related to 

 the latter; it forms a nearly regular waxen comb of cylindrical 

 cells, in which the young are hatched, and, in addition, some 

 large cells of wax for holding honey. These latter cells ai'e 

 nearly spherical and of nearly equal sizes, and are aggregated 

 into an irregular mass. Ikit the important point to notice is, 

 that these cells are always made at that degree of nearness to 

 each other, that they v>ould have intersected or broken into 

 each other, if the spheres had been completed ; but this is never 

 permitted, the bees building pel-fectly Hat walls of wax between 

 the spheres which thus tend to intersect. Hence each cell con- 

 sists 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 rests on three other cells, 

 which, from the spheres being nearly of the same size, is very 

 frequently and necessarily the case, the three flat surfaces arc 

 united into a p}Tamid ; and this pyramid, as Huber has re- 

 marked, is manifestlv a gross imitation of the three-sid(Ml jiyram- 

 'dal baseji of th(> cell of the liivc'liee. As in the fells of the 

 10 



