A complex of native parasitoids has been found to attack the citrus leafminer, Phyllocnistis citrella Stainton, since its introduction into Argentina. Elasmus phyllocnistoides n. sp., an indigenous parasitoid, that achieves parasitism levels of 0.08% to 37.7%, is described, the main morphological characters of both sexes are illustrated, and characters are given to distinguish it from other Elasmus spp. present in the Neotropical region.