206 ON THE ORIGIN OF SPECIES 



gnawed away and deepened the basins on both sides, in 

 order to have succeeded in thus leaving flat plates 

 between the basins, by stopping work along the inter- 

 mediate planes or planes of intersection. 



Considering how flexible thin wax is, I do not see 

 that there is any difficulty in the bees, whilst at work 

 on the two sides of a strip of wax, perceiving when 

 they have gnawed the wax away to the proper thinness, 

 and then stopping their work. In ordinary combs it 

 has appeared to me that the bees do not always succeed 

 in working at exactly the same rate from the opposite 

 sides ; for I have noticed half-completed rhombs at the 

 base of a just-commenced cell, which were slightly 

 concave on one side, where I suppose that the bees had 

 excavated too quickly, and convex on the opposed side, 

 where the bees had worked less quickly. In one well- 

 marked instance, I put the comb back into the hive, 

 and allowed the bees to go on working for a short 

 time, and again examined the cell, and I found that 

 the rhombic plate had been completed, and had become 

 perfectly flat : it was absolutely impossible, from the 

 extreme thinness of the little rhombic plate, that they 

 could have effected this by gnawing away the convex 

 side ; and I suspect that the bees in such cases stand 

 in the opposed cells and push and bend the ductile 

 and warm wax (which as I have tried is easily done) 

 into its proper intermediate plane, and thus flatten it. 



From the experiment of the ridge of vermilion wax, 

 we can clearly see that if the bees were to build for 

 themselves a thin wall of wax, they could make their 

 cells of the proper shape, by standing at the proper 

 distance from each other, by excavating at the same 

 rate, and by endeavouring to make equal spherical 

 hollows, but never allowing the spheres to break into 

 each other. Now bees, as may be clearly seen by 

 examining the edge of a growing comb, do make a 

 rough, circumferential wall or rim all round the comb ; 

 and they gnaw into this from the opposite sides, always 

 working circularly as they deepen each cell. They do 

 not make the whole three-sided pyramidal base of any 



