OELL-MAKING INSTINOT. 263' 



{i.e. about the width of an ordinary cell), and were in depth 

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

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

 gonal prism was built upon the scalloped edge of a smooth 

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

 pyramid 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, colored 

 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 ver- 

 milion wax left ungnawed, were situated, as far as the eye 

 could judge, exactly along the planes of imaginary inter- 

 section between the basins on the opposite side of the ridge 

 of wax. In some parts, only small portions, in other 

 parts, large portions of a rhombic plate were thus left be- 

 tween the opposed basins, but the work, from the unnat- 

 ural state of things, had not been neatly performed. The 

 bees must have worked at very nearly the same rate in 

 circularly gnawing away and deepening 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, while 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 com- 

 menced cellj which were slightly concave on one side, 



