174 
Psyche 
[June 
February, 1920. It was brought home, and during the week 
of March 25 to 30, four adults of this species emerged. 
The hollow in the stem was three inches deep, and in this 
case I could see no evidence that this tunnel had been used 
previously. The cavity contained eleven cocoons, with no 
partitions between them excepting the heavy discs de- 
scribed above. The cocoons were crowded so close together 
that some of them adhered to each other as if built together. 
The five lower cocoons contained dead larvae. Of the six 
upper ones, four had, at the time of examination, already 
given forth their adults during the week preceding, and 
two contained fully developed insects, all black and ready 
to emerge. Those which had emerged, counting downward 
from the top, were Nos. 1, 2, 3, and 5, while 4 and 6 were 
about to come forth. This suggests that the usual order 
of emergence is from top to bottom of the twig, with oc- 
casional exceptions in the case of an individual here and 
there, due to weakness, sex or some handicap. 
Another nest in a sumac twig was found to contain, on 
April 1, four bees of this species and one parasite. The 
two lower bees were in a far advanced pupal stage in their 
cells, while the two upper ones were already making their 
way out. Each insect had its hard disc above it ; above the 
uppermost one of these was a vestibule of % inch, and 
above this a loose filling, % inch in depth, of finely broken 
pith. Here too, the youngest and uppermost was the first 
to emerge, making it easy for those that were to follow. 
Her method of emergence was most ingenious. She did not 
attempt to bite her way through the hard disc forming the 
partition ; that material was too hard, and it was too diffi- 
cult to get a jaw-hold on the concave surface. So she de- 
toured and bit her way upward through the soft pith in 
the wall, making a new passage around the side of the 
obstruction. Don’t condemn her for her laziness; respect 
her for her ingenuity. 
The parasite was in the topmost cell. This adult was 
3/2 inch in length, much longer than the host and must have 
destroyed more than one young of the P. modestus. 
Up to April 12, three bees had emerged, and the last cell 
still contained its bee, which was really the eldest of the 
