ABILITY OF MUD-DAUBER TO RECOGNIZE OWN PREY 243 



Exp. 5. Next I tried a new form of interference, placing three 

 spiders in a Pelopoeus cell which was only in course of construc- 

 tion, being but one-fourth completed. So it was not at all sur- 

 prising that the wasp, after a little commotion, promptly emptied 

 this and proceeded with her masonry. 



Exp. 6. A blue wasp had completed her cell and placed her 

 first spider there. I removed it, filled the entire cell with spiders 

 from other nests and replaced her own spider in the front of 

 the cell so that she would see her own prey when she returned. 

 However, in handling the contents, I broke out a small piece 

 of the wall at the opening. When I returned in a half hour 

 I found that the cell had been emptied and deserted by the 

 mother. Why did she go to the trouble of emptying it if she 

 meant only to desert it? 



Exp. 7. A new Pelopoeus cell appeared complete, but was 

 still empty. The insect brought a load of mud, but used it to 

 reinforce the nest, then she went all the way into the empty 

 cell, and remained there for four minutes, only her tarsi pro- 

 truding. What may have been her business during this per- 

 formance we could not determine. When she had gone, thirteen 

 spiders (one with a small egg attached) from another nest were 

 placed in the cell. Upon the second and third trips she also 

 walked over her nest and deposited the mud on the outside to 

 reinforce it; she did not enter the cell, and I did not see her 

 even look inside, but when she again came she used the load of 

 mud to close the cell, then another and another until the seal 

 was firm, just as though all were normal. Whether she detected 

 the ample supply of spiders and closed the cell on that account, 

 or whether she would have sealed it empty, had we not filled 

 it for her, we could not determine. 



Exp. 8. A Pelopoeus cell was finished and quite ready for 

 use, but the larder was not yet stocked, so I filled it with spiders 

 from another nest. The mother wasp returned with a fresh 

 spider, started to enter the nest but retreated and flew out of 

 the window, taking her burden with her. She returned empty- 

 handed and carried out the intruders one by one. After the 

 cell had been empty for a half hour, I again placed eleven spiders 

 in it. The next morning when I arrived to examine this cell I 

 found it had again been emptied. 



