Field Studies of the Non-Social Wasps 459 
fiew out I placed six spiders in the cell and had not time 
to insert more when she returned with a load of mud. 
She got a glimpse of the spiders, which in this case only 
half filled the cell, and immediately flew out with the 
pellet. She threw away her mud and came hurrying 
back, peered into the cell and then bustled out again. 
She came back to the cell bent on her course of action, 
dragged out a spider and carried it away. ‘At that junc- 
ture I hurried to fill the cell completely by adding ten 
more spiders. But her zeal for righting wrongs was 
now aroused, and even this was no inducement to seal 
it up, for she carried them all out. 
Exp. XV. The new cell on this nest was just ecom- 
pleted but as yet contained no food supplies, so I placed 
in it eight fresh spiders taken from another nest. The 
mother wasp returned with a load of mud and alighted 
on the nest, but from her behavior I judge that she sus- 
pected that it was not hers, for she arose on the wing 
and flew in circles, as if seeking orientation, and re- 
turned. This she did three times, the last time making 
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 some- 
thing 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 
and throw them away, continuing until all were gone. 
Exp. XVI. A wasp was discovered putting the first 
layer on the closure of her cell. I removed this, and 
also part of the spiders, 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 
carefully opened it and inserted other spiders from an- 
