Rosefuran was identified as a female sex pheromone from an unnamed species of acarid mite, Caloglyphus sp., whose phoretic hypopi had been collected from the elongated yellowish chafer, Heptophylla picea. Behavior of sexually excited males was demonstrated by exposing them to doses of 1–100 ng of synthetic rosefuran. The pheromone was present in females and also in males and was detected in trace amounts in nymphal stages. Pheromone concentrations were estimated to be 87 ± 14.2 ng per female and 10.4 ± 2.5 ng per male. The quantitative difference between sexes may allow males to discriminate females for purposes of mating.