200 
Psyche 
[December 
places, other females were coming in from the fields. Some had 
loads of green pollen; others had yellowish-green. Could they 
be visiting different species of flowers? 2 All the while, in a con- 
stant whir of motion, the males of the colony were circling above 
the nests. Occasionally one alighted for a moment or two but 
was soon on his way. The male was not to be worried with the 
intricate problems of nesting. His was a life of pleasure. 
Fig. 1. Plan of nest of Spinoliella australior. The nests, which extend down to a depth o f 
three or four inches, contain about seven larvae. This is a vertical section of the 
earth showing all the ramifications of the nest. Coarse stippling indicates cut sur- 
face of earrh; light stippling, loose soil. (One half natural size). 
Upon digging up the nests of these bees, I was surprised to 
find that they extended no deeper than three or four inches. 
Most of the tunnels led straight down for an inch and then 
branched. So far as the galleries were open, it was clear which 
way they went. But when I reached the depth where they had 
been filled with soil, the passage-way was usually invisible. It 
blended perfectly with the surrounding clay. However, in a few 
instances, I was able to trace the galleries down to the cells. 
The general plan of these nests is shown in Fig. 1. The main 
tunnel usually branched once, and then the two passage-ways 
2 Miss Sandhouse informs me that Spinoliella australior visits the flowers 
of the following plants: Dithyrea wislizeni, Cleome serrulata and Solidago cana- 
densis. The pollen of Cleome serrulata is somewhat green. 
