Key to species (males) of genus Rhipidia from Taiwan

1 Sc2 atrophied; cell dm open by atrophy of m-m (Fig. 3); clasper of gonostylus with two slender rostral spines arising from a common enlarged basal tubercle of rostral prolongation (Figs. 4–7).............. R. (E.) formosana formosana Alexander

- Sc2 preserved; cell dm closed; clasper of gonostylus with more than two rostral spines directly arising from rostral prolongation................................................................................................. 2

2 Antenna with six bipectinate segments (Fig. 9); clasper of gonostylus with four rostral spines (Figs. 11, 13–15)........................................................................................... R. (R.) servilis (Alexander)

- Antenna with eight bipectinate segments; clasper of gonostylus not as above...................................... 3

3 Prescutum without conspicuous stripe; clasper of gonostylus with five rostral spines (Figs. 24–27).................................................................................................. R. (R.) chenwenyoungi sp. nov.

- Prescutum with a median brown stripe, lateral stripes lacking or nearly so; clasper of gonostylus with three rostral spines (Alexander 1930).............................................................. R. (R.) triarmata (Alexander)