Social- Wasps. 85 



" Having found a place suitable the deserted burrows of 

 the field-mice being perhaps more generally selected than 

 any other by the underground species, the chamber formed by 

 that animal for its nest being exactly the kind of place re- 

 quired by the insect it proceeds to attach its web to the 

 centre of the roof of the chamber. This consists, in the first 

 instance, of a pedicle, or footstalk, about half an inch in 

 length, at the extremity of which a single cell is formed, 

 which is presently surrounded by others. 



" Simultaneously with the formation of these cells, an um- 

 brella-shaped covering is prepared above them. More cells 

 are added, an egg being deposited in each of them as soon as 

 formed, while constant additions are made to the covering 

 until it has assumed a globular form, with only an aperture 

 sufficiently large for the insect to pass in and out. Before 

 the completion of the first covering, a second, just large 

 enough to enclose it, is begun, and while this is in progress a 

 third is commenced, and then a fourth, and so on. When 

 young wasps have been produced in sufficient numbers to 

 carry on the work without the assistance of the parent, an 

 event which usually takes place in about six weeks from the 

 commencement of the nest, she does not again leave home, but 

 occupies herself solely in the task of depositing eggs as fast 

 as cells can be formed by the workers for their reception. 



" There are two methods by which the nests are enlarged 

 by the workers after the queen has given up the task of 

 building ; some species choosing one, some adopting the other. 

 One consists in forming a series of regular sheets or layers, 

 which are made to overlap each other like the slates or tiles 

 on the roof of a building, in the same way as is pursued by 

 the queen of every species so long as she continues to be 

 the architect. When a few of these sheets have been com- 

 pleted, that is, when they have been made to assume a 

 spherical form, with only a small aperture for ingress and 

 egress, each internal sheet is cut away, nearly but not quite, 

 as fast as additional ones are formed externally, the shell or 

 covering therefore slightly increasing in thickness as the 

 nest increases in size. Thus architects among the human 



