148 WASPS [CH. V 



terval is accurately gauged by the workers who may from 

 time to time be seen when building to extend one leg as 

 though measuring their distance from adjacent structures. 



The number of combs may be as many as eleven, one 

 below the other; about seven is however the usual 

 number. Their general outline is circular, but they may 

 be of other shapes if the available space demands such 

 departure from the normal. I have seen combs with a 

 distinct rectangular notch upon one side caused by a 

 beam round which the workers had been forced to build 

 for want of room in other directions. 



Each cell is not occupied merely once, but so soon as 

 it is vacated by the imago, the remains of the dome- 

 shaped bottom of the cocoon are cleared away by the 

 workers, and a fresh egg is deposited by the "queen." 

 The exuviae and faecal mass of the previous occupant 

 are left in the cell, still fastened firmly to the roof. 

 There is, however, a limit to the number of times any 

 one cell is employed, probably not more than thrice ; the 

 top comb (the oldest) is often to be found with the cells 

 nearly all cut away and reduced to mere stumps; pre- 

 sumably the material removed is used in constructing 

 fresh parts of the nest. It will thus be seen that the 

 number of cells in a nest does not accurately represent 

 the numerical strength of the colony. In a nest con- 

 taining seven combs Janet counted 11,500 cells, of which 

 over 11,000 had been used twice and about 5000 thrice. 

 A large nest of ten or eleven combs might, then, have had 

 a population of some 50,000 or 60,000. 



Towards the end of the summer larger cells are con- 



