Courtship behavior in the German cockroach is typically elicited in sexually mature males by a contact sex pheromone on the cuticular surface of sexually mature females. Surprisingly, German cockroach nymphs and newly emerged adults, both males and females, also elicit courtship behavior in conspecific adult males, and nymphs retain the capacity to do so for days after their cuticle tans. Nymph cuticular extract was chromatographically fractionated (flash chromatography, HPLC) and behaviorally assayed with adult males. The active fractions were found to contain compounds that are different from any of the known female contact sex pheromone components. Behavioral assays are being used to study this mimicry throughout development. The adaptive significance of this apparent sexual mimicry system will be discussed.