150 WASPS [CH. V 



as a rule but occasionally in "royal" cells also. The 

 eggs occasionally laid by large workers invariably produce 

 males, the workers being structurally incapable of impreg- 

 nation. 



With the onset of autumn the strength of the colony 

 rapidly declines. The workers are killed off by the wet 

 and cold ; the vigour of the parent " queen " is exhausted 

 and she dies ; many of the larvae are dragged from their 

 cells and devoured by the workers ; eventually the whole 

 community, with the exception of the young queens, 

 perishes. Under the attacks of beetle larvaB and other 

 scavengers the fabric of the nest falls into ruin and decay. 

 The survivors have all mated, either within the nest or 

 upon the leaves of plants in the neighbourhood. The 

 males not infrequently mate several times, but are com- 

 paratively short-lived. The fertilised queens soon seek 

 safety in the winter quarters described above. 



The circumstances which determine whether any given 

 egg be fertilised or not, i.e. whether it shall produce in due 

 course a female (" queen " or " worker ") or a male, require 

 a few words. It is necessary first to clearly understand the 

 distribution of the sexes among the cells of the combs. 

 Fertilised eggs alone are deposited in the earlier combs : 

 at the end of July or beginning of August fertilised and 

 unfertilised eggs are laid. The latter are not placed in any 

 special cells, but in ordinary worker cells. These cells, 

 however, tend to increase in size and approximate in 

 dimensions to the "royal" cells, being intermediate be- 

 tween them and worker cells. Such intermediate cells 

 may contain large fertile workers, or true queens or males 



