A field study was carried out to determine whether small hypogaeic beetles prey on winter moth (Operophtera brumata [L.]) pupae. Small invertebrates were responsible for ca. 28% of pupal mortality at sites in British Columbia in 1991. Using a new trap design, adult Staphylinidae and beetle larvae were shown to actively search for buried pupae as indicated by significantly higher catches in hypogaeic traps baited with pupae than in unbaited, control traps. Baited and unbaited pitfalls were largely ineffective at capturing predatory larvae when compared to the baited hypogaeic traps. Many previous studies of predation on the soil-dwelling stages of insect herbivores may be biased towards the epigaeic component of the predator assemblage because they use pitfall traps alone. A combination of traps that includes hypogaeic traps should be considered for future studies.