228 THE ORIGIN OF SPECIES 



twenty times thicker than the excessively thin finished wall of the 

 cell, which will ultimately be left. We shall understand how they 

 work, by supposing masons first to pile up a broad ridge of ce- 

 ment, and then to begin cutting it away equally on both sides near 

 the ground, till a smooth, very thin wall is left in the middle; the 

 masons always piling up the cut away cement, and adding fresh 

 cement on the summit of the ridge. We shall thus have a thin wall 

 steadily growing upward, but always crowned by a gigantic cop- 

 ing. From all the cells, both those just commenced and those com- 

 pleted, being thus crowned by a strong coping of wax, the bees 

 can cluster and crawl over the comb without injuring the delicate 

 hexagonal walls. These walls, as Professor Miller has kindly ascer- 

 tained for me, vary greatly in thickness; being, on an average of 

 twelve measurements made near the border of the comb, -g^- of an 

 inch in thickness; whereas the basal rhomboidal plates are thicker, 

 nearly in the proportion of three to two, having a mean thickness, 

 from twenty-one measurements, of -^ of an inch. By the above 

 singular manner of building, strength is continually given to the 

 comb, with the utmost ultimate economy of wax. 



It seems at first to add to the difficulty of understanding how 

 the cells are made, that a multitude of bees all work together ; one 

 bee after working a short time at one cell going to another, so 

 that, as Huber has stated, a score of individuals work even at the 

 commencement of the first cell. I was able practically to show this 

 fact, by covering the edges of the hexagonal walls of a single cell, 

 or the extreme margin of the circumferential rim of a growing 

 comb, with an extremely thin layer of melted vermilion wax; and 

 I invariably found that the color was most delicately diffused by 

 the bees — as delicately as a painter could have done it with his 

 brush — by atoms of the colored wax having been taken from the 

 spot on which it had been placed, and worked into the growing 

 edges of the cells all round. The work of construction seems to be 

 a sort of balance struck between many bees, all instinctively stand- 

 ing at the same relative distance from each other, all trying to 

 sweep equal spheres, and then building up, or leaving ungnawed, 

 the planes of intersection between these spheres. It was really 

 curious to note in cases of difficulty, as when two pieces of comb 

 met at an angle, how often the bees would pull down and rebuild 

 in different ways the same cell, sometimes recurring to a shape 

 which they had at first rejected. 



When bees have a place on which they can stand in their proper 

 positions for working — for instance, on a slip of wood, placed 

 directly under the middle of a comb growing downward, so that 



