WASP'S NEST. 



as many distinct and parallel storeys. And here we may observe 

 in passing, the difference between the architectural system of the 

 wasp and that of the bee. The latter builds its cells in vertical 

 strata ranged side by side, the mouths opening horizontally so 

 that the insects in passing between stratum and stratum must 

 creep up the intervening vertical corridors ; while the wasp, on 

 the other hand, prefers horizontal corridors, so that in passing 

 between stratum and stratum it creeps over one and under the 

 other. In short, the positions given to the ranges of comb by 

 the bee, in contradistinction to that adopted by the wasp, will be 

 understood by supposing the sides of the wasp's habitation to 

 represent the top and bottom of that of the bee. 



Each comb of the wasp is composed, as shown in the figure, of a 

 numerous assemblage of hexagonal cells made of the same paper 

 as that already described, each cell being distinct, with double 

 partition-walls. These cells, unlike those of the hive bee, are 

 arranged only in a single row, the open end of each cell being 

 turned downwards and the upper end being closed by a slightly 

 convex lid, and not by a pyramidal cover like those of the honey- 

 comb. The upper surface of each stratum of comb is therefore 

 a continuous floor formed like an hexagonal mosaic, the surface 

 being nearly but not perfectly smooth, since each hexagonal piece 

 is curved slightly upwards. 



The open mouths of the cells being presented downwards, the 

 nurses as they creep along the roof of each stratum can easily 

 feed the young grubs which occupy the cells of the stratum imme- 

 diately above. The space left between one stratum and another 

 is about half an inch. 



Each stratum of comb is attached at the sides of the walls of 

 the nest, but the tenacity of the paper of which the comb is com- 

 posed would not be sufficient to sustain the weight of the stratum 

 when the cells are all filled with grubs. The little architects, 

 therefore, as though they had foreseen this, take care to connect 

 at regulated intervals each stratum with that below it by strong 

 cylindrical columns or pillars. Each of these, like the columns 

 used in architecture, has a base and a capital, to which 

 greater dimensions are given than those of the connecting 

 shaft. These columns are composed of paper similar to that 

 used for other parts of the nest, but of a more compact and 

 stronger texture. The middle strata are connected by a colonnade 

 of from forty to fifty of these pillars; the number being less 

 as the dimensions of the strata decrease in going upwards or 

 downwards. 



93. The process of building this structure is as follows. The 

 dome is first completed, as already described, by laying fifteen or 



155 



