Genus Tyrodes Raffray, 1908

[Japanese common name: Nisekoke-arizukamushi Zoku]

Tyrodes Raffray, 1908: 379 . Type species: Tyrus histrio L. W. Schaufass, 1887 (subsequent designation by Lucas 1920: 663). Tyrodites Jeannel, 1960: 455 . Type species: Tyrodites championi Jeannel, 1960 (synonymized by Besuchet 1970: 316).

Diagnosis. Head with small, nude frontal median fovea and one pair of larger, setose vertexal foveae; maxillary palpi large, each with palpomeres 2–4 each pedunculate basally, widened apically; palpomeres 4 each with sensory appendage at apex; pronotum with antebasal sulcus connecting median and lateral foveae; abdomen with tergite IV longer than V; aedeagus stout, with ovoid median lobe (Raffray 1908; Jeannel 1957; Yin & Li 2013).

Comments. The genus Tyrodes is similar to Tyrus Aubé, 1833 in their general appearances, but it is distinguished from the latter by the following characteristics: frontal median fovea small, nude (distinct, larger, setose in Tyrus); abdominal tergite IV longer than V (IV and V subequal in Tyrus) (Yin & Li 2013). In addition, after an examination of previous studies and the specimens studied in this paper, the following characteristics may also be useful for separation of both genera: male antennomeres 1 each with triangular projection on the external side of the basal part (Figs 1C, 5C) (usually lacking the triangular projection in Tyrus, but T. sichuanicus Yin & Nomura, 2013 has laterally expanded antennomeres 1), and tergite IV lacking median longitudinal carina (Fig. 3A) (usually present in Tyrus, but lacking in T. myrmecophilus Bryant, 1915) (Raffray 1908; Bryant 1915; Jeannel 1957; Besuchet 1970; Yin & Li 2013; Yin et al. 2013; Zhang & Yin 2023).

The genus Megatyrus Hlaváč & Nomura, 2003 share the characteristic of antennomeres 1 with Tyrodes, but the members of Megatyrus are easily separated from Tyrodes by the larger body, maxillary palpi with palpomeres 4 each lacking apical appendage, and tergite IV with well-defined median longitudinal carina (Hlaváč & Nomura 2003).

Among the Japanese Tyrodes species, the male shares following characteristics: posterolateral clypeal region strongly concave with demarcate edge (Fig. 2A, C, D); metaventrite with small setose projection (Figs 1E, 5D); sternite IV–V strongly concave at lateral parts (Figs 1F, 3B, 5E).