JVESTS OF APOICA. 373 



Another point in these nests is, that although they vary so 

 much in diameter, their thickness is almost uniform. The 

 reason is evident enough. As the young larvee attain a tolerably 

 uniform size, and are not boldly divided into large males, larger 

 queens, and little workers or neuters, the cells are of equal 

 length. Therefore, whether the number be great or small, the 

 thickness of the cell-group remains unchanged, though the 

 diameter may increase to any reasonable amount. 



All the nests are fixed in the same manner, a branch or twig 

 passing through the upper surface. When the nest increases in 

 size, the original support is often found to be too slight ; and in 

 that case, others are added. The smaller nests are upheld by a 

 single twig only, but the largest is supported at no less than 

 three points, two tolerably stout branches passing through the 

 side of the cover, and a smaller twig supporting the top. 



Another point to be noticed is, that the size of the nest is no 

 criterion of its shape. It is not necessarily circular because it is 

 large, nor "hexagonal because it is small. The eight examples in 

 the British Museum show every gradation of shape between 

 the hexagon and the circle, without the least reference to size. 



How the insect forms these wonderful cell-groups is an enigma 

 to which not the least clue can be found. In proportion to the 

 size of the architect, they are simply enormous, and yet the 

 sides and angles are as true and just as if they were single cells. 

 It is very clear that neither the theory of excavation or of equal 

 pressure can apply to these nests, and an additional reason is 

 afforded why these theories should be abandoned. It is to be 

 regretted that the only reasoning is of the destructive kind; but 

 at present we have no data on which to found a theory that 

 seems in the least tenable. 



In the nest to which reference has been made, the insects 

 have carried out the hexagonal principle in a curious manner. 

 A number of cells whose mouths are closed with a white silken 

 cover prove that the inmates are undergoing their metamorphosis, 

 and are in a transitional state between the larva and the perfect 

 insect. Instead, however, of being scattered at random tlirough- 

 out the nest, the inhabited cells are arranged in the most 



