' Lhe Ecology of a Sheltered Clay Bank 203 
It was on July 30 that this individual entered one of the 
burrows. When this hole was opened, a quantity of the 
resinous material was discovered, but I had no way of 
knowing whether this or another insect had done the 
storing. The Megachile bees are leaf-cutters, and make 
nests in hollow stems, but I have elsewhere* recorded 
that they have been known to make their leafy cups in 
sheltered places as under clods of earth. Some bees 
gather resinous substances, but the Megachiles are not 
known to do so. 
Another Megachile bee, M. generosa was taken while 
at rest on the bank June 3, 1921, but it is unlikely that 
its presence there was anything but accidental. 
The Osmia bee, Osmia lignaria Say. [S. A. Rohwer]. 
This little bee did not appear in the community until 
1920. In earlier researches I have found that this spe- 
cies builds its nests in mud nests of Sceliphron caemen- 
tarium. Since these bees could not offer the excuse of 
foraging as an explanation for their presence here, I at 
once suspected that they were replastering the old bur- 
rows of the other bees here for their own nests in the 
same way that they utilize the old mud-daubers’ cells. 
This I soon found to be true. ‘About a half-dozen of 
them were seen thus occupied about the bank from May 
28 to June 19, 1920, and a month earlier in 1921. They 
Were also observed gathering pollen from the black- 
berry blossoms near by. 
Spider, Ariadna bicolor Htz. [C. L. Shoemaker]. 
Of spiders, this was the most abundant species among 
the inhabitants of the clay bank, and from the first of 
— ey 
*Trans, Acad. St. Louis, 24:1-71, 1922. 
