A total of 21 species (including one new to science) of Megastigmus seed chalcids are recognized in Europe, North Africa and Asia Minor. Megastigmus spn. were found in 29 of the native conifers of Abies, Cedrus, Cupressus, Juniperus, Larix and Picea genera, in 43 of exotic conifer species introduced to Europe, in 28 spccies of Rosaceae (Amalanchier, Rosa, Sorbus) and in nine species of Anacardiaceae (Pistacia, Schinus). Fifteen species develop in seeds of conifers whilst six infest the seeds of Angiosperms (Tables 1-3).