The Ecology of a Sheltered Clay Bank 179 
The Mining-bee, Anthophora (Antheméessa) raui.* 
(S. A. Rohwer]. 
In 1917 I noticed among the turrets of Anthophora ab- 
rupta, three which turned upwards, as indicated by ar- 
rows in Fig. 9. The next year, there were five of these 
in the mass, and, since this showed a very distinctive 
digression, I concluded that this might be an advanta- 
geous variation, and began forthwith to philosophize 
upon the laws of variation, heredity, and survival of 
the fittest, with the deepest solemnity. The reason why 
the reader is mercifully spared this is that, when mak- 
ing a later visit to the place, June 13 to 19, 1920, I was 
Shocked to find about 90 of these upturned turrets, seg- 
regated into three distinct colonies, and bees, which 
greatly resembled A. abrupta, but still showed distinct 
differences, industriously taking care of them! In all 
characteristics excepting the upward turn, the turrets 
were precisely like those of A. abrupta. Since these 
bees had habits of digging, carrying water, and pro- 
visioning their nests with pollen, all of which were so 
very similar to the way of A. abrupta, it was not surpris- 
ing that they proved to be taxonomically very nearly re- 
lated to the latter species.** 
Thus the great increase in the population in 1920 
came practically as a saltation, for in 1918 they were 
Practically nil. This sudden increase seems entirely pos- 
sible, however, even though this species has the same 
Short adult life eycle that A. abrupta has for I am of 
the opinion that this bee makes more than one nest in a 
“Described in Proc. Ent. Soc. Wash. 25: Sa 1923, by Mr. Rohwer, 
who Rebbe that it is closely allied to sodal 
brupta, 
**In 1922, this species a peared three sas later than A. @ 
ated a few spaulava sues, seen a week after A. abrupta had all 
off. 
