The Ecology of a Sheltered Clay Bank 197 
bringing home their booty. The legless spider brought 
in by one of these P. mellipes was identified as Pisaurina 
undata Htz. [C. L. Shoemaker] and on another occa- 
sion a mother was seen at the base of the bank carrying 
a half-grown Phidippus spider. This versatile little wasp 
found in the old bee-holes both home and hunting- 
ground; she was actually seen to drag a spider up out 
of one burrow—its lair—and down again into another 
hole near by—her own nest. Thus we see this citizen 
finding in the clay bank ‘‘all the comforts of home,’’ 
shelter or a domicile already provided, and food sup- 
plies available near her door, and she has just as little 
work to acquire the one as to get the other, whereas in 
the usual condition, the home-makers get the benefits of 
one or the other, but seldom of both. These wasps con- 
tinue their activity throughout a fairly long season, from 
the last of May to the first of September. 
Since they made their own mud cells in the old bee 
burrows, they are classified with the renters, although 
they had just as much claim to be among the pioneers. 
Trypoxylon plesium Roh.* [S. ‘A. Rohwer]. 
Only one specimen was seen here, and it was taken at 
the clay bank on July 7, 1917. I saw this wasp actually 
walk over two distinct spider webs without becoming in 
the slightest way entangled; evidently it was on a spider- 
hunt when captured. 
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