Field Studies of the Non-Social Wasps 371 
make no cocoons, and that they arrive at maturity and 
emerge in inverse order of the deposition of the eggs, 
a. €., the uppermost matures and emerges first. They 
emerged from May 1 to 10. 
Another nest was a fortunate discovery in that it gave 
accurate data on the period of development of the young 
wasp. The nest was discovered on May 28, just when 
the mother was finishing the provisioning and oviposit- 
ing. It is noticeable that this mother was completing 
her nest 3 or 4 weeks after the wasps emerged from 
the nest described above. This may mean that a second — 
generation was being produced in the season, but we 
must not be too hasty in so concluding without con- 
sidering that the two records were made in different 
years, and the weather and temperature may have in- 
fluenced their emergence. When the wall was removed 
from one side of the twig, the cells were all found to 
be packed with wingless aphids, Schizonewra, probably 
lanigera [J. J. Davis]. One of the cells contained 
twenty-five aphids, by actual count. The egg in this cell 
was cemented to one of these, and was about two hours 
old. This afforded us an excellent opportunity to watch 
the development through the period of growth. This 
egg hatched in thirty hours. “After five days of its feed- 
ing upon the aphids, the stock was exhausted and the 
waspling lay quietly at the bottom of the cell prepara- 
tory to pupating. Two days later a slight constriction 
appeared in the middle of the upper half of the body. 
After three days more (June 9) it was a completely 
formed pupa, but without a cocoon. Five more days 
were required to complete the pigmentation, and the 
final three days were spent in spreading the wings, 
straightening the legs, and in generally expanding the 
dy. While I was examining it on June 17, it sedately 
