Helicopsyche (Petrotrichia) Ulmer, 1910

Type species: Helicopsyche palpalis (Ulmer, 1910): 44.

The genus Petrotrichia was established for a species described from Mahé Island in the Seychelles, and originally classified within the Hydroptilidae . The species was transferred to Helicopsyche by Marlier & Malicky (1979). Johanson (1998) argued for a phylogenetically close relationship between the African species of the genus (Seychelles, Madagascar and East Africa) and referred them to the subgenus Petrotrichia. Species of this subgenus are recognized by maxillary palps divided into a short basal and long distal segment, the basal segment bearing strong median setae; interantennal setal warts flat or absent; head tentorium without processes; forewing fork 3 and Cu1b absent, forewing crossvein R3­R4 directed posteriad, hind wing fork 1 longer than its stalk, crossvein M­Cu absent, Cu1 undivided; and abdominal reticulation reduced. The Madagascan species are recognized by having a longitudinal fold in the forewing, with sensillae located between veins M and Cu.