ABILITY OF MUD-DAUBER TO RECOGNIZE OWN PREY 247 



havior I judge that she suspected that it was not hers, for she 

 arose on the wing and flew in wide circles and returned. This 

 she did three times, the last time making a good many smaller 

 circles. Through all of this confused search she carried her 

 pellet. By this time she seemed fully convinced that this was 

 her home, but that something was wrong. So she dropped her 

 ball of mud out at the window, returned in a direct line to the 

 nest, and began with a very positive air to carry out the spiders 

 one by one, throwing them away until all were gone. 



Exp. 16. A wasp was discovered putting the first layer on 

 the closure of her cell. I removed this and also part of the 

 spiders, all of her own capture. The wasp came in with more 

 mud; hummed a little in anxious concern and flew out with 

 her load. She returned shortly, however, and again sealed the 

 cell. Again I opened it and inserted other spiders from another 

 nest. She came back and saw the opening, poked her head into 

 it enquiringly and proceeded to plaster it up. For the third 

 time I broke the cell, but she seemed inclined to repair it as 

 long as I would continue to damage it. 



Exp. 17. A wasp had packed her cell nicely and already 

 sealed it with two layers of clay. I carefully removed the cover- 

 ing and part of the spiders. The wasp returned with the next 

 load of mud, hesitated only a little and spread it in its proper 

 place and was off again. Again I opened it and this time in- 

 serted four foreign spiders. In due time the mother returned 

 and again plastered the opening as if nothing had happened and 

 departed. Bent on commanding her attention I broke the seal 

 for the third time and placed a larva of Pelopoeus in the door- 

 way, half protruding, so she could not seal the compartment 

 without removing it. By the time she arrived with a pellet 

 this larva had worked itself out of the cell, so she spread the 

 mud as usual over the cell. When she had again gone I 

 tried another very large larva in the same way. The mother 

 wasp returned, made no attempt to remove the larva, or in 

 fact displayed no concern for its presence, but spread the 

 mud around it as it lay half protruding from the cell, often 

 severely jarring it as she worked, plastering her mud to the 

 sides of the larva as though it were a part of her wall, and thus 

 again sealing in this silly fashion her cell. 



Exp. 18. To a Pelopoeus cell containing a few spiders I 



