462 Trans. Acad. Sci. of St. Louts 
Not having other spiders at hand, I placed a pupal case 
containing a pupa of the same species in her cell so that 
no part protruded. When I returned two hours later 
the cell was sealed and a fifth cell was half completed. 
I had to break open the cell to see if the pupa had been 
removed. The cell was empty, but the new item of in- 
terest was that at six o’clock the next morning I found 
this damaged cell repaired and the fifth cell still in its 
half-finished condition. This was the first case in my 
experience of a wasp going back and giving attention to 
a previously finished cell after a subsequent one had 
been begun. 
Exp. XX. The mother was filling the cell with spi- 
ders; the eight which she had already stored were re- 
moved. She returned several times, but brought in no 
more after she first found that her property had been 
disturbed, and finally abandoned it. 
Exp. XXI. <A nest was being provisioned, when all 
ten spiders were removed at 8:35 a.m. When the wasp 
found the cell empty, she spent the next five hours in 
bringing in mud and reinforcing various parts of the 
nest, and at 3 p. m. she sealed it up empty. 
Exp. XXII. The one spider in the cell was removed. 
At intervals during the day, the mother was seen to 
carry mud and spread it in various parts of the nest, 
but in the afternoon she sealed it empty. 
Exp, XXTIT. At 8:30 a. m. the five spiders were re- 
moved from a cell which was then being provisioned, but 
here too the response of the owner was the same as 
before, and finally at 1:45 she sealed it empty. 
Exp. XXIV. A five-celled mud nest lay flat on the 
floor. I attempted to remove the spiders from a cell 
that was being stocked, when the returning wasp caught 
me in the act. Seeing her spiders disturbed, she re- 
