370 Trans. Acad. Sci. of St. Louis 
to the opposite wall and downward (fig. 47): The ma- 
terial forming the partitions was the finely chewed pith 
packed rather loosely, and unused portions of the chan- 
nel were in places filled with this same material, as 
though it had been carelessly kicked or dropped there. 
Undoubtedly the material when bitten out of the main 
channel is carried out and dropped to the ground. In 
making the side pockets, the pith is probably more care- 
lessly tossed about. Many wasps mix this pulverized 
pith with saliva to make strong, compact partitions, but 
here it is so loosely placed that a puff of wind blows 
it away. 
The main channel was 1014 inches from the top aper- 
ture to the bottom. This, plus the seven lateral cells, 
must have made a heavy task of excavating for so tiny 
a creature. The lowermost end of the main channel (a) 
was used for a cell; it was 14 x 5g inch, but had been 
sealed empty. The partition at its top was 4 inch 
thick, and immediately on top of this was (b) a cell of 
dead and dried plant lice but no egg. Above this the 
passages from the point ‘‘c’’ to ‘‘d’’ and the neck above 
the lowermost side pocket (e) were filled with pith which 
Was 80 loose that it seemed to have been merely thrown 
im or kicked down. Three of the lateral cells, ‘‘f,”’ 
““g”? and ‘‘h,’? each gave forth an adult wasp, while the 
other three cells (x) as well as the remainder of the 
main channel above ‘‘d’’ to the point ‘‘i’’ were filled 
with the loose, soft pith. The remaining upper portion 
of the tunnel was empty. 
The next twig home of D. biparitor was so similar to 
the one just described that the explanation of the figure 
seems quite sufficient. There were five cells, two of 
which were made out of the lower extremity of the main 
channel. From this nest I learned that the young wasps 
