CELL-MAKING INSTINCT 283 



about one-sixth of the diameter of the sphere of which they 

 formed a part, the rims of the basins intersected or broke 

 into each other. As soon as this occurred, the bees ceased to 

 excavate, and began to build up flat walls of wax on the 

 lines of intersection between the basins, so that each hex- 

 agonal prism was built upon the scalloped edge of a smooth 

 basin, instead of on the straight edges of a three-sided pyra- 

 mid as in the case of ordinary cells. 



I then put into the hive, instead of a thick, rectangular 

 piece of wax, a thin and narrow, knife-edged ridge, coloured 

 with vermilion. The bees instantly began on both sides to 

 excavate little basins near to each other, in the same way as 

 before; but the ridge of wax was so thin, that the bottoms 

 of the basins, if they had been excavated to the same depth 

 as in the former experiment, would have broken into each 

 other from the opposite sides. The bees, however, did not 

 suffer this to happen, and they stopped their excavations in 

 due time ; so that the basins, as soon as they had been a little 

 deepened, came to have flat bases; and these flat bases, 

 formed by thin little plates of the vermilion wax left un- 

 gnawed, were situated, as far as the eye could judge, exactly 

 along the planes of imaginary intersection between the 

 basins on the opposite sides of the ridge of wax. In some 

 parts, only small portions, in other parts, large portions of a 

 rhombic plate were thus left between the opposed basins, 

 but the work, from the unnatural state of things, had not 

 been neatly performed. The bees must have worked at very 

 nearly the same rate in circularly gnawing away and deep- 

 ening the basins on both sides of the ridge of vermilion wax, 

 in order to have thus succeeded in leaving flat plates between 

 the basins, by stopping work at the 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-com- 

 pleted rhombs at the base of a just commenced cell, which 

 •were slightly concave on one side, where I suppose that the 



