OCCUPANCY BY HYLAEUS OF SUBTERRANEAN 
HALICTID NESTS (HYMENOPTERA: APOIDEA) 1 
By Edward M. Barrows 
Department of Entomology, University of Kansas 
Lawrence, Kansas 66045 
Hylaeus (Colletidae) is well known to nest in various preformed 
cavities. It is most commonly reported in hollow stems (Stoekhert, 
1933 ; Malyshev, 1936; Michener, 1965; Stephen et al., 1969) but 
also may occupy cynipid wasp galls (Stoekhert, 1933; Laroca, 1971) 
and dead wood (Perkins, 1899; Michener, 1965). However, nest 
sites are not limited to plant materials. Smith (1855) reported cells 
in hollow pieces of “flint stone”; Ferton (1932), in earthworm bur- 
rows; and Perkins (1899), in ground. The present paper concerns 
nests of H. bisinuatus 2 in burrows of a halictine bee in an earthen 
bank ; this is the first record of Hylaeus occupancy of nests of another 
hymenopteran. 
H. bisinuatus has also been found in North America nesting in 
soda-straw traps and nail holes (R. R. Snelling, pers. comm.) and in 
Europe in hollow briar ( Rubus ) stems (Stoekhert, 1933). Thus 
this species evidently has behavior which is flexible enough to enable 
it to nest in a variety of preformed holes in a wide geographical area. 
In early July to early August, 1974, six nests of H. bisinuatus 
were found among those of Lasioglossum ( Dialictus ) zephyrum 
(Halictidae: Halictinae) in a nesting aggregation in vertical banks 
of the Kansas River, near Eudora, Douglas County, Kansas. Al- 
though the Lasioglossum nest aggregation is enormous, extending for 
about 1 km up and down the river, all the Hylaeus nests were found 
in about 10 square meters where the bank faces northwest. 
The burrows occupied by H. bisinuatus were obviously former 
nests of L. zephyrum. In two nests vacant cells of L. zephyrum were 
near those used by H. bisinuatus ; abandoned cells of L. zephyrum 
probably would have been found in all nests by following main bur- 
rows farther into the soil. Cells of Hylaeus were constructed in 
cells of the Lasioglossum still having the shape and wax-like lining 
Contribution No. 1580 from the Department of Entomology, University 
of Kansas, Lawrence, Kansas. 
2 H. bisinuatus (Forster, 1871), described from Europe, is a senior synonym 
of H. stevensi (Crawford, 1913), described from North America, where it 
is probably aidventive (R. R. Snelling, pers. comm.). 
Manuscript received by the editor } April 5, 1975 
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