Field Studies of the Non-Social Wasps 433 
the cells just which tiers had been constructed first. They 
had not been made in consecutive order; the second tier 
had been made to the right of the first, the third to the 
left of the first, and the fourth to the left of the third; 
in other words, the tiers in order of their manufacture 
stood 4, 3,1, 2. Tiers 1 and 3 had four cells each, 2 had 
three cells, and 4 was still being filled. 
On July 21 I found that the nest begun on June 29 
was now a nest of two tiers, complete, and the parent 
wasps were gone. One tier had five cells and the other 
one four. At this date all the cells had fully developed 
pupae, showing that from egg to pupation is less than 
23 days in T. politum. 
The form of TJ. politum nests is sometimes unique. 
One nest consisted of only one pipe, 20 inches long. The 
mother, instead of making a series of pipes as usual, 
seemingly got up her momentum in making one pipe, and 
never stopped until it had attained this surprising length, 
and enclosed enough space to make a normal complete 
nest. This was built into an angle of the woodwork, with 
a distinct saving of material and labor, and the wasp 
adapted herself to this convenience. We should like 
much to know to what extent she was aware of her in- 
genuity and economy! 
The progress of the construction of another nest was 
watched. It took the wasp three weeks to build two tiers 
of four inches each. The illustration (fig. 60) shows all 
that it accomplished from the time it first commenced 
until ‘August 13, or three weeks. The unusual method 
of building the second tier before filling and partitioning 
the first one was here seen. The usual order of busi- 
ness of 7’. politum is to build a tier, bring in spiders, 
oviposit and build the partition, and repeat this process 
until the tier is filled; then build a second tier. In the 
