Tachysphex austriacus Kohl, 1892 and T. pompiliformis (Panzer, 1804) (Hymenoptera, Crabronidae) are a complex of fourteen species in Europe and Turkey

Tachysphex pompiliformis (Panzer, 1804) and Tachysphex austriacus Kohl, 1892 species subgroups belong to the Tachysphex pompiliformis species group, and both subgroups consist of morphologically similar species. The Tachysphex austriacus Kohl species subgroup comprises four species in Europe and Turkey. For this subgroup, differential diagnoses of Tachysphex austriacus and Tachysphex prismaticus Straka, 2005 are presented, and Tachysphex hungaricus sp. n. from Hungary and Tachysphex smissenae sp. n. from Spain, France and Turkey are described. The Tachysphex pompiliformis species subgroup consists of ten species from Europe and Turkey. For this subgroup, differential diagnoses of Tachysphex ferrugineus Pulawski, 1967 and Tachysphex opacus F. Morawitz, 1893, as well as the differential diagnosis and redescription of Tachysphex pompiliformis, are presented. Tachysphex dimidiatus (Panzer, 1809), Tachysphex jokischianus (Panzer, 1809) and Tachysphex nigripennis (Spinola, 1808) are resurrected from synonymy with Tachysphex pompiliformis and redescribed. Neotypes of Tachysphex dimidiatus (Panzer) and Tachysphex nigripennis (Spinola) are designed. Tachysphex bohemicus sp. n. from the Czech Republic; Tachysphex cretensis sp. n. from Crete, Greece; Tachysphex nobilis sp. n. from Bulgaria, the Czech Republic, Hungary, Poland, Slovakia and Turkey; and Tachysphex punctipleuris sp. n. from Bulgaria, Germany, Hungary, Italy, Slovenia and Turkey are described. Identification keys to all species from Tachysphex pompiliformis and Tachysphex austriacus species subgroups known from Europe and Turkey are presented.