148 
Psyche 
[September 
does not need to build skyward, for her nests are in the trees, 
where she has ample space wherein to expand normally. 
The P. rubiginosis nests were usually built in the dark space 
between the weatherboarding and the inside wall of an old house. 
One was also placed in a narrow space between two upright 
timbers, and as the nest grew to fill the entire space it took on 
the peculiar oblong shape. But the space was apparently not 
sufficient, for on the back of the nest a row of 10 cells (arrows in 
fig. 4) was begun. The shape of the normal nest is probably 
round with the petiole in the center. In this case, the petiole 
had not sufficient strength to hold the mass, and as the season 
neared its close, the nest fell and lodged on a joist below. 
Thus, to the credit of at least some species of Polistes, let it 
be said that wasps do not yield to defeat when the nest has out- 
grown its quarters, but they make the best of the situation and 
continue building. Let it be said, too, to the discredit of some 
members of these species, that they have not the foresight to 
choose sites large enough to accomodate the growing family, 
but that too late they discover their cramped quarters. 
These nests reveal the formation of a habit which may some 
day be developed with some degree of permanency. They show 
that the wasps have discovered, or stumbled upon, the fact that 
both sides of the wall or roof can, in emergency, be used to 
support cells. Alas! it is too much to hope that we may in our 
brief lifetime see the crystallization of a degression, adaptation 
or new economy like this into a regular habit. That type of 
nest, i. e., with cells attached to both sides of the main supporting- 
platform, thus making them open in opposite directions, is made 
by Belonogaster junceus of the tropics. 
One small nest of a P. pallipes queen which differed from 
the normal in its method of attachment to its support was ob- 
served. It was only a quarter-inch below the roof of a railway 
shed, yet it was attached to a vertical timber; hence the petiole, 
which is usually vertical and straight, made a horizontal be- 
ginning and turned sharply downward elbow-wise. It is obvious 
that a nest could never attain any considerable size in that 
position. 
Vespa builds combs in tiers and Polistes builds but a single 
