Hercostomus is a genus of flies in the family Dolichopodidae.

[4] It is a large genus, containing more than 483 species worldwide.

[5] Multiple studies have shown that Hercostomus is a polyphyletic assemblage of species.

[2][6][7] The genus currently includes the following species groups, at least 25 of which are known from China:[8] The Palearctic species of Hercostomus are traditionally separated into five numbered groups, based on the coloration of the femora, postocular setae and antennae:[5] In 1999, Igor Grichanov divided the Afrotropical species of Hercostomus into three numbered groups.

[20] Two of these have since been separated into their own genera:[21]