Species of sap beetles present at a central Illinois cornfield—oak woodland habitat were determined by spring to fall collections from can traps baited with fermenting wheat dough and banana.Carpophilus lugubrisMurray was the dominant species.Glischrochilus quadrisignatus(Say) andStelidota geminata(Say) were also collected frequently. Other species collected commonly wereC. antiquusMelsheimer,C. freemaniDobson, andColopterus truncatusRandall, which were generally encountered only in the early spring and late fall. Peak collections ofC. lugubriswere in late April, early June, and throughout the fall. A similar trend was noted forG. quadrisignatus, butS. geminataonly had late spring and fall peaks. The peaks occurred at fairly consistent intervals over all 3yr forG. quadrisignatusandS. geminata, but the spring first generation peak forC. lugubriswas retarded by 3–4 wk during 1988. This change in population distribution might have resulted from the long dry period that occurred during this time.