Key to Procloeon species from the Chinese mainland (Nymph)

1. Maxillary palpi two segments (Fig. 4F).................................................... P. strumiferum sp. n.

-. Maxillary palpi three segments (Figs. 4D–E)................................................................ 2

2. Posterior margins of terga dark (Fig. 5C); apical half of caudal filaments brown (Figs 5C–D)................. P. chinensis

-. Posterior margins of terga pale (Fig. 5A); brown band present subapically (Figs 5A–B).................... P. pennulatum

Key to Procloeon species from the Chinese mainland (male and female imagoes)

1. Hindwings lack costal projection (Fig. 1D)................................................. P. strumiferum sp. n.

-. Hindwings with hooked costal projection (Figs 1B–C)........................................................ 2

2. Hindwings slender (Fig. 1B).................................................................. P. pennulatum

-. Hindwings relatively wide (Fig. 1C).............................................................. P. chinensis