190 Trans. Acad. Sci. of St. Louis 
bers than in 1917; by 1920, the population had trebled. 
Just why this habitually sand-digging Larrid should 
choose to adopt itself to the yellow clay of the bank, and 
why after this change, it should flourish and increase 
in numbers, is still an unanswered question. 
We see only slight relation between this wasp and the 
other inhabitants of the clay bank, since these mothers 
must go abroad for the Orthopterous prey; hence prob- 
ably it had nothing in common with its neighbors other 
than occasionally falling prey to the spiders there. 
The devil’s horse, Stagmomantis carolina Linn. 
The egg-cases of the devil’s horse were often found 
plastered to the boards above the bank, and each June 
the little nymphs could be seen walking about the bank. 
They are carnivorous, and probably fed upon some of 
the very small insects about the bank, until they in turn 
fell prey to spiders that were occupying the old burrows. 
The paper wasp, Polistes pallipes Lepeletier. 
During the four years there were probably a dozen 
nests of P. pallipes on the under side of the porch and 
attached to the rose bushes in front of the bank; but in 
so far as I could see, the wasps had no relation to the 
unit as a whole, since they. made their own nests, and 
did not get prey from the clay-bank; neither did they fall 
prey to the inhabitants. Sometimes, they built their nest 
in narrow spaces between boards, which resulted in nests 
strangely shaped, but the point which remained most 
puzzling was that every year some should persist in 
building in this cramped space between two joists, and 
making these unusual nests, when there were hundreds 
of square feet of clear ceiling and wall space ready to 
accommodate them. 
