Key to Trisuloides species, based on male genitalia

1. Harpe long, positioned longitudinally, along plate of valve..................................................... 2

- Harpe relatively short, positioned transversal............................................................... 4

2. Harpe digitiform, apically rounded or abrupt................................................................ 3

- Harpe bifurcate, apically pointed (Fig. 57)....................................................... T. catocalina

3. Harpe long, reaching dorsal or ventral margin of valva, apically rounded (Figs. 58–60)....................... T. sericea

- Harpe relatively short, not reaching dorsal or ventral margin of valva, apically abrupt (Fig. 61).............. T. prosericea

4. Apex of valva abrupt, costa tipped, harpe comb-like (Fig. 64)............................................ T. becheri

- Apex of valva rounded, costa not tipped, harpe not comb-like................................................... 5

5. Harpe tooth-like....................................................................................... 6

- Harpe conical, serrate laterally, with prominent lateral extension (Fig. 64)................................... T. zhangi

6. Harpe tooth-like, flat, with two smaller basal extension and larger distal extension (Fig. 62)................... T. taiwana

- Harpe bifurcate, with two conical extensions about equal in length (Fig. 63)........................... T. rotundipennis