452 Trans. Acad. Sci. of St. Louis 
large spider, and spent some time in laboriously cram- 
ming it in. Quite satisfied now with her store, she 
brought balls of mud and duly closed up the cell. While 
she was gone for another load, I picked open the cell and 
extracted a part of the contents. Arriving at the nest 
with the next pellet of mud to reinforce the closure, she 
saw the injury and at once took alarm, hurried out and 
threw away the mud, returned and with clearly ex- 
pressed indignation carried out the remaining spiders 
one by one, her own as well as mine, until the nest was 
stark empty, and departed. 
Exp. I. While another §. caementarium was gone 
from home, I stirred up the spiders which she had 
placed in her cell and added one from another nest. 
When she returned, she promptly carried it out and 
made four more trips, each time carrying out a spider 
of her own capture, until all were gone. Then after a 
brief, unexplained absence she came back and inspected 
the empty cell, fretted about and examined and stood 
guard over it for an hour and a half, all because a few 
spiders had been disturbed. 
Upon returning three hours later, I found the cell 
sealed. I opened it and found just two medium-sized 
spiders, with an egg attached to one. Thus this mother 
was so anxious about her progeny that she carried out 
and rejected all the spiders which had been touched by 
human hands or forceps, and now she sealed up the egg 
with only sufficient food to carry it half through its 
larval life. 
Exp. III. One day while collecting nests I removed 
a large one from a shelf against the barn wall. No 
sooner done than a blue wasp, Chalybion caerulewm, re- 
turned to it. She examined the spot very carefully for 
about thirty minutes. When at last she flew out, I re- 
