46 



PHIL RAU AND NELLIE RAU 



in the case of the remaining cells still to be accounted for she 

 probably was responsible to some extent. 



Number of cells provisioned and sealed without the egg 



Of the remainder of the cells we find 537, or 12 per cent, of 

 the total, in which the mothers had completed the cell, ade- 

 quately provisioned it and finally sealed it without laying the 

 egg. This defect of instinct or intelligence is appalling when 

 one thinks of the effort expended in building the nests and the 

 great amount of spider hunting necessary to provision them. 

 We tabulated the number of spiders that came -out of 515 of 

 these cells, as follows: 



Total 4,637 Average 9 



Thus the effort spent in capturing and storing 4,637 spiders 

 (an average of 9 to a cell) was utterly futile because the mother 

 wasp failed to deposit an egg with them. We find the number 

 of such cells in each nest varying from 1 to 17 and occurring 

 with the following frequency. 



275 



537 



