Figures: 12, 40, 48, 58, 65, 107, 245
In addition to the Heptageniinae characteristics, the following combination of characteristics will identify the genus:
The fan shaped robust setae on the abdominal terga are unique to Trichogenia (Fig. 107). Additionally, combination of minute lamellae of gills 1, narrow, pointed lamellae of gills 2-7, and an Oriental distribution will differentiate Trichogenia from other Heptageniinae larvae (some Palearctic species of Heptagenia have gill lamellae similar to those of Trichogenia, but lack the fan shaped robust setae).
The combination of a long pair of spines on ventral surface of penes and forewings with violet coloration should differentiate males of Trichogenia from other Heptageniinae genera. Only one species, tentatively placed in Trichogenia, is known in the adult stage. Because Trichogenia is the only Heptageniinae genus known from southeast Asia, identification should not be a problem.
Southeast Asia (Fig. 245).