The mystery of where virgin female Microsepsis armillata (Melander & Spuler) copulate has been solved with the discovery of sexual activity in small aggregations that are not tightly associated with the oviposition sites, where matings have been observed previously in this and other sepsid species. Nonvirgin females also mate in these aggregations, and matings at such sites may help explain the otherwise puzzling variations in male precopulatory riding behavior in other sepsids. Approximately 25% of the unpaired females in aggregations carried an unlaid egg in her bursa, and larvae had hatched from some of these eggs. Retention of a bursal egg could prevent intromission by males.