Methanol, acetaldehyde, and ethanol have been identified in extracts of attractive wood and bark. The attractancy induced by anaerobic treatment in both sapwood and phloem of conifers and broadleaf trees was characterized by ethanol as the most concentrated component. In laboratory bioassays, ethanol was attractive at low concentration to both sexes ofTrypodendron lineatum(Olivier). Methanol and acetaldehyde, at the concentrations found, apparently play no role in attraction. Monoterpenes had a repellent effect onT.lineatum.