Key to the final stadium larvae of Taiwanese Polycanthagyna species

1. Cerci parallel-sided, female ovipositor reaching only 3/4 of S10..................................... P. erythromelas

- Cerci with inner margin curved outwards apically, female ovipositor reaching at least the posterior margin of S10......... 2

2. Paraproct 2.0 times as long as cerci, cerci with inner margin strongly and suddenly curved outwards apically; female ovipositor extending far beyond S10.................................................................. P. ornithocephala

- Paraproct 1.6 times as long as cerci, cerci with inner margin slightly and smoothly curved outwards apically, female ovipositor reaching to posterior margin of S10............................................................. P. melanictera