The Nesting Habits of the Burrowing Bee, Epinomia Triangulifera Vachal

Epinomia triangulifera is a large bee, recorded heretofore, according to W. Dwight Pierce, 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 o the city. These bees seem to have a strange liking or 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, or 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 ew nests of this species were seen during the warmer months of three years. On September 1 o the fourth year, 1918, when this spot was examined, they were ound in enormous numbers. The conditions 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 portions o the hill-top were also abundantly occupied. This region was covered with g.rass 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