146 WASPS [CH. V 



to make room for extension and fresh coverings are added 

 externally. This process is frequently repeated as the 

 need arises and entails much labour on the workers. 

 The coverings not only afford protection against rain (in 

 arboreal species) but are also of great importance in 

 enclosing layers of air and thus preventing the escape 

 of the heat generated within the nest. Janet and Guiot 

 have found that the temperature within a flourishing 

 nest is about 88 F. and may exceed that of the outside 

 air by 25 F. to 30 F. 



When adding fresh "paper" to the existing fabric a 

 wasp works backwards, thus avoiding contact with the 

 newly applied material. This has been reduced to pulp 

 and is then laid on by means of the jaws ; all the while 

 the antennae are kept playing upon both sides of the old 

 and of the new material as though testing its thickness. 



In the central portions of the comb the cells are 

 all very regularly hexagonal, but near the margins they 

 are frequently less regular and approach a cylindrical 

 shape. When the first comb has reached a convenient 

 size, which is determined by the dimensions of the 

 cavity in which the nest is being built, a number of 

 pillars of "wasp-paper" are built downwards from the 

 angles of the cells. At the lower ends of these pillars a 

 second tier of cells is built similar to the first, and so on 

 with each successive tier as the needs of the colony 

 demand. Thus the fourth comb is hung from the third, 

 the third from the second, the second from the first, and 

 the whole from the original platform laid by the " queen " : 

 this however has ere now been strengthened to bear the 



