Merodon trizonus (Szilady, 1940) nomen dubium

Remarks.

The identity of Merodon trizonus remains unclear. The species was described based on two male and two female syntypes labelled "La Calle [el Kala], Algeria" and "Ain Draham, Tunisia", which were not examined. Originally, the syntypes were located in the Hungarian National Museum in Budapest, but the Diptera collection was destroyed by a fire in 1956. The description of Szilády (1940) is incomplete and based on a few differences from the related species M. hirsutus . The types of M. trizonus are assumed lost and the description is insufficiently accurate to associate name to one of these species. Currently, two species from the M. serrulatus species group, to which M. hirsutus belongs, occur in northern Africa, namely M. bequaerti and M. sophron. Therefore, we propose to leave the name Merodon trizonus ( Szilády, 1940) as nomen dubium.