166 
Psyche 
[September 
when she attempted to work it into the turret it would 
crumble and fall to the ground. The size of the population, 
it seemed to me, was just as much regulated by the amount 
of water available as by the number of parasites, for in 
1922, when hundreds of bees were at work and the fewest 
turrets were made, the official statement from the local 
weather bureau at St. Louis showed that the precipitation 
for the five months, May to September inclusive, was the 
least recorded in 85 years. 
In another colony, in a different locality, the nests were 
also built without turrets, but in that case the deficiency 
was due to lack of clay instead of water. Here the mothers 
were nesting in the disentegrating mortar of an old stone 
chimney. Despite the fact that so little turret material was 
available, and no normal chimneys were made, a good many 
of the tunnels had a very small ring or collar at the opening. 
This bee was almost contemporaneous with A. raui (fig. 
6) ; however, interbreeding of the two species was not pos- 
sible. Careful observations in 1922, showed that A. abrupta 
emerged from May 30th to June 2nd, and by June 3rd all 
the males were dead. A. raui did not appear until June 
10th, a week after the males of A. abrupta were gone. This 
made it impossible for the males of A. abrupta to fertilize 
the females of A. raui and since the females of A. abrupta 
had already been fertilized when the A. mm 'emerged, a 
second fertilization was improbable. In 1929, the A. abrupta 
population waned on about July 2, and the A. raui about 
July 12. 
Since A. raui Rohwer is a new species, reported so far 
only from this particular clay bank, it would be fascinating, 
if justifiable, to surmise that this habitat is the cradle of the 
species, an offshoot from A. abrupta. 
We may cite for comparison some observations on other 
species of this genus in various localities by different in- 
vestigators. 
Sharp 1 says Anthophora is one of the most extensive and 
widely distributed of the genera of bees. He also points out 
that Friese has made the discovery that A. per sonata 2 at 
1 Insects. Pt. II, p. 33, 1899. 
2 A. personata is now called A. fulvitarsis Brulle. (fide T. D. A. Cockerell). 
