BEES AND WASPS- ARCHITECTURE. 
175 
plate of wax had been thick enough to admit of the oppo- 
site basins being deepened (and widened) into cells, the 
mutual intersection of adjacent as well as opposite bottoms 
would have given rise, as in the first experiment with the 
thick plate of wax, to the pyramidal bottoms. Experi- 
ments with the vermilion wax also showed, as Huber had 
previously stated, that a number of individual bees work 
by turns at the same cell ; for by covering parts of grow- 
ing cells with vermilion Tvax, Mr. Darwin — 
In variably found that the colour was most delicately diffused 
by the bees — as delicately as a painter could have done it with 
his brush — by atoms of the coloured wax having been taken 
from the spot on which it had been placed, and worked into the 
growing edges of the cells all round. 
Such, omitting details, is the substance of Mr. Darwin’s 
theory. In summary he concludes, — 
The work of construction seems to be a sort of balance 
struck between many bees, all instinctively standing at the 
same relative distance from each\pther, all trying to sweep 
equal spheres, and then building up, or leaving ungnawed, the 
planes of intersection between these spheres. 
This theory, while serving as a full and simple expla- 
nation of all the facts, has, as we have seen, been so fully 
substantiated by observation and experiment, that it de- 
serves to be regarded as raised to the rank of a completed 
demonstration. It differs from the theory of Buffon in 
two important particulars : it embraces all the facts, 
and supplies -a cause adequate to explain them. This 
cause is natural selection, which converts the random 
‘ pressure 5 in Buffon’s theory into a precisely regulated 
principle. Random pressure alone could never produce 
the beautifully symmetrical form of the hexagonal cell 
with the pyramidal bottom ; but it could and must have 
produced the intersection of cylindrical cells among pos- 
sibly many extinct species of bees, such as the Melipona. 
Whenever this intersection occurred in crowded nests, it 
must clearly have been of great benefit in securing 
economy of precious wax ; for in every case where a flat 
wall of partition between two adjacent cells did duty 
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