BEES AND WASPS ARCHITECTURE. 173 



ledge. Usually in such cases the final explanation is 

 eventually reached by the working of a yet greater mind, 

 and in this case the undivided credit of solving the 

 problem is to be assigned to the genius of Darwin. 



Mr. Waterhouse pointed out * that the form of the cell 

 stands in close relation to the presence of adjoining cells.' 

 Starting from this fact, Mr. Darwin says, 



Let us look to the great principle of gradation, aud 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 theii 

 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. ... In the 

 series between the extreme perfection of the cells of the hive- 

 bee and the simplicity of those of the humble-beo we have the 

 cells of the Mexican Melipona domestica, carefully described 

 and figured by Pierre H.uber. ... 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 are nearly spherical and of nearly equal sizes, 

 and are aggregated into an irregular mass. But the important 

 thing to notice is, that 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 completed ; 

 but this is never permitted, the bees building perfectly flat cells 

 of wax between the spheres which thus tend to intersect. Hence 

 each cell consists of an outer spherical portion ; and of two, 

 three, or more 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 

 are united into a pyramid ; and this pyramid, as Huber has 

 remarked, is manifestly a gross imitation of the three-sided 

 pyramidal base of the cell of the hive-bee. . . . 



Reflecting on this case, it occurred to me that if the Meli- 

 pona had made its spheres at some given distance from each 

 other, and had made them of equal sizes, and had arranged them 

 symmetrically in a double layer, the resulting structure would 

 have been as perfect as the comb of the hive-bee. Accordingly 

 I wrote to Prof. Miller of Cambridge, and this geometer has 

 kindly read over the following statement, drawn up from his 

 information, and tells me that it is strictly correct. 



