Abstract We conducted a detailed study of the internal genitalic characters of males and females of Copris klugi klugi Harold and Copris klugi sierrensis Matthews. On the basis of the adopted taxonomic criteria and on the comparison of eight species included in the fricator group, we maintain that C. klugi Harold and C. sierrensis Matthews are distinct species rather than subspecies. At the same time, although with only preliminary results, we also emphasize the heterogeneity of some species complexes that were established by Matthews and are recognized in the literature, and underline the need for a group revision using genitalia as a source of taxonomic data. In addition to the taxonomic analysis, we also included an introductory revision of the geographic distribution of the two studied taxa and their related species.