382 Trans. Acad. Sci. of St. Louis 
hausted her, however, for at the end of the seventh day 
she was still in this position. 
At this juncture a second wasp was discovered just 
beneath the first, which had evidently been waiting for 
her to go on to break the way. She had previously es- 
eaped my notice, having been buried in the crumbled 
pith. The first one had passed a cocoon three inches up; 
this was intact, but bore small incisions, which had prob- 
ably been made by the pioneer. The fully developed pupa 
therein was dead, but its dried-up condition gave every 
evidence that it had died at a much earlier date, and that 
the elder brother had not been responsible for its death. 
The cocoon next above this one was in the same condi- 
tion. The original position of the second emerging adult 
was not ascertained ; its empty cocoon could not be found; 
it had been broken by the young wasps which were de- 
molishing everything in their way in trying to force an 
exit. On March 28, close examination showed that both 
these young wasps were dead; neither had moved since 
the last examination, ten days previously. The tight 
plug evidently had been too much for them to puncture, 
or perhaps the extreme efforts made by the pioneers 
when such a large amount of packing was moved was 
the cause of their exhaustion. 
Another stem occupied by H. stirpicolus was taken im 
Tower Grove Park on March 25, 1919. On April 17, the 
fifth one from the bottom was out of its cocoon and kick- 
ing about in the crumbled pith; it must have turned itself 
about thus, for it was facing downward. During the 
next two days all seemed to come suddenly to maturity, 
so that on April 19, three of them were already out of 
the gallery and resting on the outside of the stem en- 
Joying the full light of their new day, and three others 
were in the open upper part of the gallery; but since 
