Key to Eurystylus species known from Japan and Taiwan

1. Pronotum almost entirely fuscous, concolorous, without noticeable pale portion or macula (Fig. 3 H, J)...... E. jingfui n. sp.

- Pronotum grayish brown, pale brown, or brown, usually with a pair of darker spots on disk...........................2

2. A pair of dark spots on pronotum surrounded by pale margin, clearly ocellate (Fig. 2 A); final-instar nymph with four or five pairs of clear, ocellate spots on abdominal sterna II–VII (Fig. 2 B)................................... E. coelestialium

- A pair of dark spots obscure, ovoid, narrowed (Fig. 1 E–F) or sometimes absent (Fig. 3 A); final-instar nymph usually with two pairs of ocellate spots on abdomen (Fig. 2 C–D)..............................................................3

3. Antennal segment III entirely dark, without pale base; paired spots on pronotum ovoid and comparatively clear (Fig. 1 D; 3E); corium and clavus speckled with grayish, mossy patterns (Fig. 3 E); final-instar nymph with almost uniformly whitish or yellowish body, antennae and legs (Fig. 2 D)................................................... E. ryukyus n. sp.

- Base of antennal segment III always pale; paired spots on pronotum elongate and obscure (Fig. 1, E–F), sometimes reduced or obliterated (Fig. 3 A); hemelytron speckled with small, pale spots, without mossy pattern (Fig. 3, A, C); final-instar nymph generally pale brown, partly tinged with red, with apical parts of antennal segment II and femora reddish brown (Fig. 2 C)................................................................................................. E. sauteri