1929] 
The Nesting Habits of Epinomia 
243 
THE NESTING HABITS OF THE BURROWING BEE, 
EPINOMIA TRIANGULIFERA VACHAL 1 
By Phil Rau, 
Kirkwood, Mo. 
Epinomia triangulifera is a large bee, recorded here- 
tofore, according to W. Dwight Pierce 2 , from New Mexico, 
Kansas and Nebraska. In St. Louis it was found in large 
colonies on two clay hillocks in a vacant lot comprising a 
few acres in the heart of the city. These bees seem to have 
a strange liking for elevated areas, for in this sunny region, 
which was a favorite haunt of so many Hymenoptera, only 
these two colonies on the hillocks were found. For want of 
a temporary name, I called them the “knoll-bees,” and was 
much interested to find that Mr. Pierce had been impressed 
with the same characteristic, for he also records having 
found them in colonies and on elevations “a foot or so above 
the surrounding ground.” 
On the gentle slope of a knoll, a few nests of this species 
were seen during the warmer months of three years. On 
September 1 of the fourth year, 1918, when this spot was 
examined, they were found in enormous numbers. The con- 
ditions which obtained in that place or year must have been 
exceptionally favorable to this species, in order to produce 
so many. The most densely populated portion was the area 
sloping gently toward the southwest, although the level por- 
tions of the hill-top were also abundantly occupied. This 
region was covered with grass of a wiry nature, growing 
sparsely on the clay soil, with occasional patches entirely 
barren. Both amidst the grass and on the uncovered 
areas their domes of excavated earth were to be seen; in 
1 Identified by J. C. Crawford. 
2 Univ. Nebr. Stud. 4: 29. 1904. 
