Dasypogon diadema was first described from Italy and is known from France, Germany, Greece, Spain and the former Yugoslavia. Records from other countries must be rechecked to eliminate the new species described by Weinberg (1979 - 1991). Existing studies show that D. diadema is the most common species of the group in Europe and predominantly inhabits the central region of the Northern Mediterranean. Its northern border is situated in the central part of Germany.
The following German records are known: Jaennicke (1868) from Eberstadt and Jugenheim, Kittel & Kriechbaumer (1868) from Nürnberg, Regensburg and the Bavarian mountains, Neuhaus (1886) from the Mark Brandenburg, Sack (1907) from Auerbach and Jugenheim, Rapp (1942) from the Höllental and Halle (Saale), Miksch et al. (1993) from Schwetzingen and Darmstadt and Geller-Grimm (1996) from Darmstadt, Eberstadt, Griesheim and Viernheim.
Three records have not previously been published: Frankfurt/Oder, without date, Riedel leg., 1 female [Museum Darmstadt, HLHD]; Lampertheimer Heide (north of Mannheim, 49°36ŽN 8°32ŽE), 04.VII.1995, Bathon leg., several specimens [pers. comm.] and Dudenhofen (east of Speyer, 49°20ŽN 8°24ŽE), 09.VII.1995, Bettag & Geller-Grimm leg., 1 male.
It appears from the above that the current distribution is limited to the upper valley of the Rhine, where the soil is mainly sandy and the temperature is normally the highest in Germany.