Westwood, J.O. 1881. Notae Dipterologicae. No. 5. - Descriptions of new species of exotic Tipulidae, with an annotated summary of species belonging to the same family, previously described. Transactions of the Entomological Society of London 3: 364.
The genus Trentepohlia is extensive, being represented by nearly 300 species and strongly represented in the Oriental Region. The species of Trentepohlia may be separated from other genera by the characteristic shape of the singular male gonostylus and characters of the wing venation that shows the loss of the R-M crossvein and the deflection of CuA2 towards A1, at times intersecting and closing off cell cup. The subgeneric divisions of Trentepohlia are based on variation in the wing venation and are easily separated based on various combinations of wing characteristics.
Trentepohlia (Mongoma) is the most species rich of the subgenera of Trentepohlia with 140 species. The subgenus does not has a single trait it is separated from the remaining subgenera of Trentepohlia, but may be separated based on the combination of wing characters: three branches of Rs to wing margin, two Medial veins to wing margin, cell dm present, and CuA2 intersecting A1 closing cell cup.
Head: Anterior vertex not produced. Rostrum length less than or subequal to that of the remaining head. Maxillary palpus length subequal to the remaining head, palpomeres subequal; Antennae: 16 articles, antenomeres suboval to cylindrical.
Wing: Subhyline to lightly suffused; stigma present or absent, additional coloration uncommon; anal angle present. Wing venation: Sc long, Sc1 removed from Sc2, Sc1 ending after split of Rs; Sc2 may be absent; R1+2 subequal to R2, R2 typically directed toward wing base; three branches of Rs (R3, R4, R5) attaining wing margin, R3 and R4 strongly divergent; R-M crossvein absent; two Medial veins (M1+2, M3) attaining wing margin; cell dm present; one Cubital veins (CuA1) attaining wing margin, tips divergent; CuA2 intersecting A2 at wing tip, closing cell cup; two Anal veins (A1, A2) attaining wing margin.
Male hypopygium: 9th tergite (9t) and sternite (9s) varialbe, typically a fused ring but may be separated by lateral margin or ventral division. Mesoventral lobe of gonocoxite present or absent. Gonostylus singular; style a broad flattened sclerotized lobe, a tooth present at about 1/3 the length of the style, tip variously produced. Aedeagus simple with one or two terminal openings. Proctriger simple, without modification
Trentepohlia (Mongoma) is an extensive subgenus that finds it highest species richness in the Oriental Region (71 species). This subgenus is widely distributed and commonly encountered throughout the Oriental Region, with collection records indicating its presence near and around aquatic areas. Outside of the Oriental Region T. (Mongoma) is additionally found in the Australian/Oceanic (46 species), Afrotropical (22 species), Eastern Palearctic (3 species), and Neotropical (1 species) Regions.
The larvae of this subgenus have been found in decaying plant stems from Java (Alexander 1919; De Meijere 1911)
