The Ecology of a Sheltered Clay Bank 235 
these and the white banded bees declined simultaneously 
with the increase in this parasite. 
I do not know what happened to the species in 1919, 
but in 1920 they appeared in limited numbers, and in 
1921, they were again on the increase. 
This fly evidently has a sensational criminal life his- 
tory, which I hope some day will be brought to light. 
Ganperdia apivora Aldrich [J. M. Aldrich]. In June, 
1920, a dozen or more specimens of this red-eyed diptron 
were flying about the burrows in the clay bank, in a 
manner strongly indicating parasitic habits, although I 
did not at any time actually see them enter the burrows, 
and the same observation was made on May 27 to May 
28, 1921. These bees are undoubtedly parasitic on the 
mining bees in the clay bank, since I actually observed 
them hatching in the laboratory from cells of Antho- 
phora abrupta on May 20 to 22, 1921, from material 
taken about nine miles north of the clay bank. 
This species is described by J. M. Aldrich* from spec- 
imens taken near St. Louis in 1877. It is very interest- 
ing, too, that forty-five years ago this fly was found in 
a clay bank about the nests of the mining bee, Antho- 
phora abrupta. That it is parasitic upon these bees is 
evident from the statement in the paper cited, that one 
‘of the bee cells contained cocoons which gave forth 
adult flies of this species in the following Spring. 
In the first week of June, 1922, hundreds of these red- 
eyed flies were out at the bank and were then being 
freely preyed upon and devoured by the lizard (Cnemt- 
dophorus sealineatus) which made itself at home about 
the place. 
*Proc. Ent. Soc. Wash. 21:106. 1919. 
