160 Trans. Acad. Sci. of St. Louis 
activity which occurred in the north half in contrast to 
that in the south half will be seen by the contrast of the 
great number of holes in the one to the lack of them in 
the other. Before the summer was far advanced, the 
cause for the occupancy of one portion of the bank and 
not of its opposite half was clearly apparent. ‘A glance 
at Fig. 2 will show how the central and south rose- 
bushes had been trained to overshadow the southern por- 
tion of the clay bank, while the third bush had been so 
bent as to leave the northern half exposed to the eastern 
sun.* This shows beautifully the relation of sunlight 
to the activities of Hymenoptera. The loose appellation 
usually applied to them, ‘‘Children of the Sun,’’ is here 
seen to have truthful significance. It is generally known 
that bees and wasps love the sunlight, but a glance at 
Figs. 3 and 4 will forcibly emphasize this impression. 
While this clay bank was small and unimposing, its 
riddled portions indicated that many bees and in all 
probability their parasites were potentially present, and 
for an ecological unit for intensive study nothing better 
could be wanted. Accordingly, frequent visits were 
made to the spot from June 5 to October 3, 1917, and 
several trips were made there for comparative data dur- 
ing the summers from 1918 to 1921. 
When one looks at Fig. 2 and thinks of the life, love 
and death tragedies enacted within the limits of an area 
of a few square feet, one can see very clearly a literal 
example of the statement by Adams: ‘‘ We may profitably 
compare an association of animals in a given habitat to 
a play upon the stage. The environment corresponds to 
*The photograph for figure 2 was taken in October, when most 
of the leaves had fallen, and so does not give an adequate idea of 
the density of the shade. 
