Genus Physatocheila Fieber, 1844

Physatocheila Fieber, 1844: 80. Type species by subsequent designation (Oshanin 1912: 45): Acanthia quadrimaculata Wolff, 1804 (= Acanthia costata Fabricius, 1794).

Phyllochisme Kirkaldy, 1904: 280. Type species by subsequent designation (China 1943: 247): Acanthia quadrimaculata Wolff, 1804 (= Acanthia costata Fabricius, 1794). Synonymized by Horváth (1906: 94).

Diagnosis. Recognized among other tingid genera by a combination of the following characters: body elliptical or rhomboid; maximum width across hemelytra wider than maximum width across paranota; head shorter than its maximum width across compound eyes, with five spines; antennal segments I close to each other at their bases; bucculae contiguous with each other at anterior ends; rostrum not reaching abdominal sternite IV; pronotum convex in anterior part, tricarinate; lateral margin of pronotum not emarginate in anterior part; hood roof-shaped, lower than pronotal disc at highest part; pronotal carinae carinate; paranotum reflexed, expanding inward, without longitudinal ridge, occasionally bulged upward in posterior part, occasionally forming a cyst; outer margin of paranotum resting on pronotal disc in its entire length; posterior process well-developed; anterior margins of hemelytra not parallel to each other at rest; costal area distinct; subcostal area subhorizontal or subvertical; discoidal area flat; Cu (cubital) and R+M (radiomedial) veins carinate; hypocostal laminae with a single row of areolae in its entire length; ostiolar peritreme well-developed; metasternum as wide as or wider than mesosternum; metasternal laminae separated from each other at posterior ends; abdominal sternites IV–VIII in male and IV–VII in female each with a transverse furrow throughout their width; pygophore elevated at center of venter; ovipositor with well-developed ovivalvula at base; and paratergite IX in female unilobed.

Remarks. The genus Physatocheila comprises 57 species worldwide (Drake & Ruhoff 1965a, 1965b; Duarte Rodrigues 1982b, 1992; Péricart 1982, 1983, 1984, 1985a; Livingstone & Jeyanthibai 1994; Péricart & Golub 1996; Guilbert 1997, 2002; Göllner-Scheiding 2007; Aukema et al. 2013; Matocq 2016; Guilbert & Guidoti 2018; Souma, 2019). In Japan, six species, including P. distinguenda, P. fieberi, P. miyatakei, P. nigrintegerrima, P. orientis, and P. veteris, have been recorded to date (Jakovlev 1880; Baba 1925; Takeya 1930, 1951; Drake 1942; Miyamoto 1964; Golub 1977a; Péricart 1982; Miyamoto & Yasunaga 1989; Yamada & Tomokuni 2012; Yamada & Ishikawa 2016; Souma 2019). Here, we identified nine Physatocheila species from Japan. Although we confirmed an additional indeterminate species, we did not treat in the present study because only a single specimen in a poor condition was available. Although keys to the Japanese species of the genus were presented by Yamada & Tomokuni (2012) and Souma (2019), we provide a key to these nine species below.

Physatocheila and Cysteochila are the most closely related to each other among the tingid genera, and their delimitation has been discussed in the late 20 th century, as already mentioned in the Cysteochila section above. According to Péricart (1979, 1982, 1983, 1992), Physatocheila can be distinguished from Cysteochila by the following characteristics: paranotum not bulged upward in posterior part, not forming a cyst; outer margin of paranotum resting on pronotal disc in its entire length; metasternum as wide as mesosternum; metasternal laminae nearly parallel to each other; and ovipositor with well-developed ovivalvula at base. However, P. fieberi (Figs. 8E, F, 9E, 10E, 11E, 17G, H, 18G, H) matched the definition provided by Péricart (1979) in terms of the paranotum bulged upward in the posterior part, forming a cyst. Meanwhile, based on the comparison of the type species P. costata (Fig. 15A–D) and C. tingoides (Fig. 3A–D), of Physatocheila and Cysteochila can be easily differentiated based on three major characteristics: maximum width across hemelytra wider than maximum width across paranota; lateral margin of pronotum not emarginate in anterior part; and metasternal laminae separated from each other at posterior ends. Consequently, we redefined the morphological characteristics shared by Physatocheila species, as described in the Diagnosis section above.

Physatocheila resembles Oncophysa Stål, 1873 in general appearance but can be distinguished from the latter by the anterior margins of the hemelytra not parallel to each other at rest and the distinct costal area. In contrast, Oncophysa has the anterior margins of the hemelytra nearly parallel to each other at rest and the indistinct costal area.