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. 

 Again, 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, 



