BEKS AND WASPS — ARCHITECTURE. 
173 
ledge. Usually in such cases the final explanation is 
eventually reached by the working of a yet greater mind 9 
and in this case the undivided credit of solving the 
problem is to be assigned to the genius of Darwin. 
Mr. Waterhouse pointed out 6 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, and so© 
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-bee 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. . . . 
Befiecting 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. 
