THE HEXAGONAL PRINCIPLE. 587 



up because the nests that would set them -at rest belonged to an- 

 other group. We will first take the central nest. 



The specimen from which this was drawn was fortunately in 

 an unfinished state, only eight cells being made, and some of these 

 but partly finished. As the reader may see by reference to the 

 illustration, all the cells are hexagonal, whether finished or in- 

 complete, and, moreover, that the edges of the hexagon are quite 

 sharp and well defined. 



Now, if either of the two theories were true, the cells would not 

 have assumed this shape. Where are the six surrounding cells 

 that are needed to compress the outermost cell into an hexagonal? 

 Or where are the six surrounding cells from which the hexagon 

 was excavated ? There are none. The outermost cell, for exam- 

 ple, is perfectly free on five of its sides, being only attached to the 

 neighboring cell by the sixth side. Compression, therefore, has 

 not been employed, because there is nothing that can compress it ; 

 neither has excavation been used, because there is no material to 

 be excavated. No one, on looking at this group of cells, can deny 

 that the hexagonal form is produced by the direct labors of the 

 insect, and not by any secondary mechanical means. 



Perhaps some one who has not examined the actual object 

 might say that the materials of which the cells are made are suf- 

 ficiently stiff to need no support of contiguous cells. Now the 

 substance of this remarkable nest is singularly slight, the walls 

 being not thicker than the paper on which this account is printed, 

 and the material is quite soft, as may be seen by the curvature 

 produced by the mere weight of the structure. Yet none of the 

 cells are united by more than three sides, the greater number by 

 two only, and the external cells merely by a single side, leaving 

 five sides and four angles perfectly free. 



In this particular specimen the material has evidently been va- 

 ried, the insect having been forced to employ different substances 

 in forming its home, as is seen by the pale and dark rings altern- 

 ately surrounding the cells. The insect which makes this curious 

 home is of moderate size, and is grayish -black, banded with yel- 

 lowish-white. The abdomen is tolerably stout and sharp-pointed, 

 and is attached to the thorax by a short brownish foot-stalk. This 

 insect is a native of Natal. Other species of the same group will 

 be mentioned in the course of the following pages. 



In the left-hand upper corner may be seen a very remarkable 



