Cuticular hydrocarbons of adult Roptrocerus xylophagorum (=eccoptogastri) (Ratzeburg) from California and Georgia were isolated and characterized by combined gas chromatography-mass spectrometry. The hydrocarbon compositions of individuals from both locations were very similar with the major components of n-alkanes, midchain-methylbranched alkanes, terminally methylbranched alkanes and 3,7-dimethylbranched alkanes. Hydrocarbons of the females were shorter (average chain length 28.7) than the hydrocarbons recovered from the males (31.5). Cuticular hydrocarbons of R. xylophagorum females from Belgium, Austria and Switzerland were primarily alkenes, n-alkanes and alkadienes, whereas the major components of males from Belgium were n-alkanes, alkanes and terminally methylbranched alkanes. Cuticular hydrocarbon profiles of R. xylophagorum collected in Europe were very different from those of R. xylophagorum from the United States but very similar to Roptrocerus mirus collected in Switzerland. R. xylophagorum adults from Australia that were progeny of those introduced from the United States had cuticular lipid profiles similar to those of the parasitoids collected in North America.