176 
ANIMAL INTELLIGENCE. 
instead of a double cylindrical wall of separate cells, there 
wax should have been saved. Thus we can see how 
natural selection would have worked towards the develop- 
ing of an instinct to excavate cells near enough together 
to produce intersection ; and once begun, there is no 
reason why this instinct should not have been perfected 
by the same agency, till we meet with its ideal perfection 
in the hive-bee. For as Mr. Darwin observes, — 
"With respect to the formation of wax, it is known that 
bees are often hard pressed to get sufficient nectar ; and I am 
informed by Mr. Tegetmeier that it has been experimentally 
proved that from twelve to fifteen pounds of dry sugar are con- 
sumed by a hive of bees for the secretion of a pound of wax ; so 
that a prodigious quantity of fluid nectar must be collected and 
consumed by the bees in a hive for the secretion of the wax 
necessary for the construction of their combs. Moreover, many 
bees have to remain idle for many days during the process of 
secretion. . . . Hence it would continually be more and more 
advantageous to our humble-bees if they were to make their 
cells more and more regular, nearer together, and aggregated into 
a mass, like the cells of Melipona ; for in this case a large part 
of the bounding surface of each cell would serve to bound the 
adjoining cell, and much labour and wax would be saved. 
A gain, from the same cause, it would be advantageous to the 
Melipona if she were to make her cells closer together, and 
more regular in every way than at present ; for then, as we 
have seen, the spherical surfaces would wholly disappear and be 
replaced by plane surfaces ; and the Melipona would make a 
comb as perfect as that of the hive-bee. Beyond this stage of 
perfection in architecture, natural selection could not lead ; for 
the comb of the hive-bee, as far as we can see, is absolutely 
perfect in economising labour and wax. 
The problem, then, as to the origin and perfection of 
the cell-making instinct appears thus to have been fully 
and finally solved. I shall now adduce a few facts to show 
that while the general instinct of building hexagonal 
cells has doubtless been acquired by natural selection in 
the way just explained, it is nevertheless an instinct not 
wholly of a blind or mechanical kind, but is constantly 
under the control of intelligent purpose. Thus Mr. Darwin 
observes,— 
