242, Trans. Acad. Sci. of St. Louis 
tion of the sun-loving parasites to the position of the 
nests of their hosts, and (c) the action of parasite to- 
ward host as the nest of the host is in the sunny or the. 
shady portion of the bank. 
Position of the clay bank in relation to the sunlight. 
We have seen in Fig. 2, how the clay bank was 
protected above by the porch and faced the eastern sun. 
Three clumps of rambler rose-bushes stood in front of 
the bank, one at the north end and two spread over the 
south half. These were densely covered with flowers 
and foliage during the summer.* Since two rose-bushes 
were in the southern half, the portion of the clay bank 
just behind them was much more shaded than the north- 
ern half. 
In this brilliantly illuminated area between the bushes 
the nests of 4. abrupta abounded; here they left their 
old burrows, an unmistakable record of the life which 
had been there. It was in this portion of the bank also 
that in 1917, the most of the contemporaries of the 
Anthophora congregated to build their nests. It would 
be better to say that here they emerged, and then re- — 
mained in almost the precise spot to nidify, but this in 
turn only means that their ancestors at some time ac 
tually chose this spot or congregated here, so the signi- 
ficance is the same. In order to realize the sharp con- 
trast in the nesting activities, between the sunny poT- 
tion of the bank and the shaded areas, Figs. 3 and 4 
may be compared. Fig. 4 shows the northern half 
(the photograph was taken after a dry year, when few 
bees made turrets, and these few had fallen or had been 
*This picture was taken in October, when most of the foliage 
had fallen. 
