Supplementary diagnostic characters of genera in the tribe Discocerinini are suggested. A new genus Aquachasma Zatwarnicki, type species: Discocerina leucoprocta Loew, 1861 is described with 24 new combinations of all included species. Genus Polytrichophora is divided into the nominate subgenus and a new subgenus Sklodowskopa Zatwarnicki, type species: Clasiopa duplosetosa Becker, 1896. Genus Orasiopa is divided into the nominate subgenus and a new subgenus Reymontopa Zatwarnicki, type species: Discocerina mera Cresson, 1939. The shape of the proboscis of all genera of Discocerinini is provided, including variability of cibarium and pseudotracheae. The ventral receptacles of 6 genera (Aquachasma, Facitrichophora, Galaterina, Hydrochasma, Lamproclasiopa, and Pectinifer) are illustrated for the first time. Additional support for generic status for recently established taxa (Orasiopa, Lamproclasiopa, Galaterina, and Facitrichophora) is documented. The revised relationship among Discocerinini genera based mostly on proboscal characters is proposed. Four groups are distinguished — 1) Gymnoclasiopa group with nominate genus, 2) Diclasiopa group with Diclasiopa, Ditrichophora, Hecamedoides and Pectinifer, 3) Lamproclasiopa group with Galaterina, Lamproclasiopa, Orasiopa (subgenera Reymontopa and Orasiopa) and 4) Discocerina group with Aquachasma, Discocerina, Facitrichophora, Hydrochasma, and Polytrichophora (subgenera Polytrichophora and Sklodowskopa).