Field studies made with newly emerged (unmated) female Popillia japonica Newman, collected from clusters of Beetles proved that such females have a powerful volatile Sex pheromone When these females were tethered or conlined Fined in traps in an area where large numbers of adults Were emerging they attracted males within seconds. A Single unmated female per trap per trap and 9 unmated females per trap attracted 380 and 2975 males, respectively, in a single hour, and 3 traps each containing 9 unmated females (collected on successive days) attracted 19,248 males and 345 females between July 7-9 and September 5, 1968, though 85% were attracted within the 1st week. After the removal of attractive females, glass and metal containers continued to attract males up to 30 min, Exposure of isolated female abdomens and of heads plus thoraces showed that the attractant substance was produced in the abdomen. However, various solvent extracts of abdomens were not attractive.