The Oriental neotenic net-winged beetles attracted attention of biologists due to conspicuous large-bodied females; nevertheless phylogenetic relationships remain contentious and only a few species are known in both the fully metamorphosed males and neotenic females. The phylogenetic analyses and morphology of larvae and adults provide data for investigation of relationships and species delineation. Platrilus Kazantsev, 2009, Platerodriloplesius Wittmer, 1944, and Falsocalochromus Pic, 1942 are synonymized to Platerodrilus Pic, 1921. Platrilus hirtus (Wittmer, 1938) and Pl. crassicornis (Pic, 1923) are transferred to Platerodrilus Pic, 1921. Platerodrilus hoiseni Wong, 1996 is proposed as a junior subjective synonym of Falsocalochromus ruficollis Pic, 1942. Platerodrilus is divided in three species-groups: P. paradoxus, P. major, and P. sinuatus groups defined based on the shape of genitalia and molecular phylogeny. The following species are described: Platerodrilus foliaceus sp. n., P. wongi sp. n. (P. paradoxus group); P. ngi sp. n., P. wittmeri (P. major group), P. ijenensis sp. n., P. luteus sp. n., P. maninjauensis sp. n., P. montanus sp. n., P. palawanensis sp. n., P. ranauensis sp. n., P. sibayakensis sp. n., P. sinabungensis sp. n., P. talamauensis sp.n., and P. tujuhensis sp. n. (P. sinuatus group). P. korinchiana robinsoni Blair, 1928 is elevated to the species rank as P. robinsoni Blair, 1928, stat. n. The conspecific semaphoronts are identified using molecular phylogeny for P. foliaceus sp. n., P. tujuhensis sp. n., P. montanus sp. n., P. maninjauensis sp. n.; additional female larvae are assigned to the species-groups. Diagnostic characters are illustrated and keys are provided for P. paradoxus and P. major groups.
