Species of the Cheloninae subfamily have the first three metasomal segments fused, forming a carapace, and the other segments are hidden. Cheloninae are therefore easy to distinguish. The genus Chelonus differs from the genera Ascogaster and Phanerotoma by the absence of the vein 1-SR+M, which in Ascogaster separates the wing cells D1 and Sm1 (see explanation of wing veins and cells).
Ascogaster species can be keyed out with the use of Huddleston 1984, and Phanerotoma species with van Achterberg 1990. For the western European species of Chelonus there is no good key available, and species information is scattered over dozens of papers. In this website I try to combine all pieces of information on Chelonus species, add some photographs, and try out an experimental key to help identify these species.
