Field Studies of the Non-Social Wasps 353 
which she obtained by breaking down and carrying away 
other parts of the old nest. When she had first begun 
to make her cells herein, she had evidently gotten her 
mud from the very same cell, for enough had been re- 
moved about the opening to enlarge it to two or three 
times its normal size and the edge was all scarred with 
mandible-marks. This cell is known as ‘‘H.’’ 
P. mellipes was on the nest at the time of its discov- 
ery, but left as I approached. After a lapse of nine 
minutes she returned, flew into cell ‘‘X,’’ presently 
came out and flew into her own cell ‘‘H.’’? She went in 
head first; the abdomen partly protruded and showed 
every indication that she was at work within the cell. 
Evidently when she entered cell ‘‘X’’ she removed a 
mouthful of mud from one of the walls, and within the 
cell which she had appropriated she was busily fashion- 
ing it into her own cells. The next two mouthfuls proved 
the correctness of this assertion, for she was next ac- 
tually seen biting out mouthfuls of mud from the broken 
cell on top and carrying this material into the cell she 
was reconstructing. Since these pellets were not car- 
ried out, it is evident that they went into her masonry. 
Thus she removed six loads from the wall and took 
them down into her cell; then she went out and returned 
in 12 minutes. Throughout the period of observation 
She often left. the nest, undoubtedly for water, and re- 
turned each time after an interval of about two min- 
utes. The light was dim in the corner of the shed under 
the roof where she was at work, and I could not see 
whether she moistened the dirt first before removing it 
or wet it as she was actually at work biting it out with 
her jaws. Of only this much I was certain: that the soil 
as she carried it in her mouth was wet and glistening, and 
very close scrutiny revealed that the spot where she got 
