We investigate a number of scorpion populations from southern and central Europe, commonly classified under a “catch-all” name of Euscorpius carpathicus (L., 1767). This species includes a high number of described subspecies but its composition is not resolved. The detailed morphology analysis in the present paper includes a number of new characters, in particular individually mapped external patellar accessory trichobothria. It suggests that several clearly separated lineages are present. E. carpathicus (L.) is restricted here to geographically marginal populations from Romania (terra typica), which exhibit loss of one trichobothrium in the patellar series em (= 3). Another lineage (Austria, Croatia, Italy, France, Slovenia) is characterized here as E. tergestinus (C.L. Koch, 1837); it has a “standard” trichobothrial number in the patellar series eb (= 4), eba (= 4) and em (= 4) and exhibits only variation in the ventral and et series. This species includes as new synonyms the following seven subspecies described by Caporiacco (1950): E. c. apuanus, E. c. concinnus, E. c. niciensis, E. c. aquilejensis, E. c. picenus, E. c. oglasae, and E. c. corsicanus. A very distinct Balkan lineage is delineated based on unique trichobothrial numbers in patellar series eb (= 5) and eba (= 7); it is elevated here to the species status as E. hadzii Caporiacco, 1950 (Albania, Bosnia, Bulgaria, Croatia, Greece, Macedonia, Yugoslavia). This species includes as a new synonym E. c. lagostae Caporiacco, 1950. The fourth species-rank taxon confirmed here is E. koschewnikowi Birula, 1900 (Greece), with “standard” trichobothrial number in the patellar eb (= 4), eba (= 4) and em (= 4) series but with other unique morphological features. We fix neotypes of E. tergestinus and E. hadzii, and a lectotype of E. koschewnikowi. These four species and E. balearicus Caporiaccebao, another member of this complex, are contrasted in detail using trichobothrial patterns, morphometric ratios and carinal development trends as diagnostic characters.