Disparlure (cis-7,8-epoxy-2-methyloctadecane), the sex pheromone of the gypsy moth,Porthetria dispar(L.) (Bieri et al. 1970), and 55 related compounds (Sarmiento et al. 1972) were tested in Japan as attractants for the so-called Japanese gypsy moth,P. d. japonica(Motschulsky). The Japanese gypsy moth closely resembles the North American species, but it is much larger (as much as 50%). Authorities at the United States National Museum of Natural History consider the Japanese gypsy moth a distinct Subspecies ofP. dispar.