176 Trans. Acad. Sci. of St. Louis 
for that year. These pages will show that each year 
immediately after this, the second mining-bee, Entechnia 
taurea, comes upon the scene and continues the mining 
activities. The bees were observed for five years, and 
their numbers ran practically in inverse ratio to those 
of A. abrupta; as the one increased, the other decreased. 
These white-banded bees (Fig. 7) emerged from the 
clay bank in 1917 on about July 16, and took up their 
work on the spot. This species likewise made turrets 
over its burrows, but they were a little smaller in size 
and of finer texture than those of A. abrupta. Like A. 
abrupta, these bees did not seal their burrows, either at 
the end of the chimney or the mouth of the burrow.* 
The males of this species do not seem to emerge before 
the females; or at least, if they do, they do not die earlier, 
for on July 311 saw a lot of frolicsome males nea 
at the north end of the bank. 
The activities of the white-banded bees ne 
throughout the summer. They never swerved from their 
self-restricted nesting areas, two spots at the extreme 
ends of the clay bank. By August 14, the burrows of 
these bees were becoming somewhat abundant, and the 
dancing males had now spread themselves to the south 
end, where they buzzed and danced about the busy fe- 
males coming home heavily laden with pollen. While 
some of the latter burrowed horizontally into the face of 
the bank, others dug vertically into the flat top. They 
seem to have a preference for the top, since about ninety 
per cent of the nests were there. These bees, like their 
predecessors, also carried water to moisten the hard clay 
*One scoring finds the turrets sealed at the orifice, but in 
all the specimens of ‘bis kind which I examined, the burrows 
been usurped poses used by the wasp, Tryporylon clavatum. 
