Male mating behavior elicited by solvent extracts of males in the yellow-spotted longicorn beetle, Psacothea hilaris (PASCOE), was examined. When a gelatin capsule was coated with the extract of male elytra or elytra-removed body, male responses were similar to those elicited by female extracts, although less intense. These pheromonal activities were observed at more than 2-3 male equivalent/capsule but decreased at higher doses. Among the different body parts of males, male 'dash' toward the treated capsule was elicited most strongly by prothorax extracts. Abdominal bending response was released by all the extracts except for those from the antenna and head. The distribution of active substances on the male body was those from the antenna and head. The distribution of active substances on the male body was similar to that of the female pheromone. When prothorax extract was mixed with other body extracts, male response was reduced, which suggested the presence of a masking substance.