Indigenous and introduced seed chalcids in Denmark - with a revised key to the Danish species (Hymenoptera: Torymidae).
The paper describes the occurrence and plant relationship of Danish species of Megastigmus Dalman, 1820. Five species are new to the Danish list, viz. M. atedius Walker, 1851, M. milleri Milliron, 1949, M. rafni Hoffmeyer, 1929, M. specularis Walley, 1932 and M. borriesi Crosby, 1913. They are all introduced. The indigenous species M. bipunctatus (Swederus, 1795) is now represented by specimens from known localities. A key to adult males and females of the 12 Danish species is given. The routes of introduction and response to food plants (a wide variety of forest trees) are discussed.