The Ecology of a Sheltered Clay Bank 249 
taurea, will burrow without regard to the light, that it 
chooses dark areas as well as well-lighted ones without 
any apparent detriment to the work, but here it is ap- 
parent how, especially after a cold night, the sun indi- 
rectly influenced the amount of work done by warming 
up the nest and routing the sleepers. After all we must 
admit, that despite the fact that these bees often built 
their nests back in the shadow of the porch, they seldom 
did work when the sun had passed beyond the zenith, 
leaving the bank more shaded. It is interesting to note 
that in the afternoon, after the deeper shadows fell upon 
the bank at about 2 p. m. the activities of several spe- 
cies were at their minimum. An analogous condition 
existed on dark or cloudy days. The insects behaved 
much as the population of a normal site would at twi- 
light. As the shadows lengthened, some spiders would 
become active, thus adding the suggestion of night- 
prowlers to the twilight setting. 
“‘September 4. While I have elsewhere recorded that 
as the sun warms up the bank, more and more of the 
Entechina bees come out of their holes and begin work, 
it is now my pleasant duty to record that this rule is 
not absolute, for today the behavior is reversed. Yes- 
terday they were working intensely at their digging; 
now it is dull and dreary after the heavy rain in the 
night, yet the bees have been busily at work carrying in 
pollen. In so far as I can see, this reversal of behavior 
can be due only to the fact that much rainy weather 
lately has caused a set-back in their work, and they be- 
&in to ‘realize’ that if ever they are going to get their 
domestic duties done before Gabriel sounds his trumpet, 
they will have to be up and doing despite weather con- 
ditions. 
