Epeurysa nawaii Matsumura, 1900

(Figures 1–4)

Type locality. Japan (Gifu).

Amended description. Color. General body coloration (Figs 1A–B) uniform, dull brown. Forewings clear transparent to weakly embrowned, sometimes with dark markings at apex of clavus and/or just proximad of ScP along costal margin. Abdominal segments reddish brown except pygofer and gonostyli dark brown (Fig. 1D).

Structure. Body length ♂: 3.47 mm (n=4, 3.26–3.60 mm), ♀: 3.79 mm (n=6, 3.65–3.91 mm).

In dorsal view (Fig. 1A), vertex quadrangular, short (width approximately 3.2× midlength), sublateral carinae arched from anterior margin of eyes, meeting medially just before head apex; in lateral view (Fig. 1B), head depressed below level of pronotum, body with hump-backed appearance; head in profile with vertex declinate, fastigium rounded (clypeus receded from level of frons). Frons broad (Fig. 1C, height at midline approximately 1.2× greatest width), subquadrate, lateral margins laterally bowed (widest near midlength); median carina distinct, forked near fastigium to form indistinct areolet between arms and sublateral carinae of vertex at dorsal margin of frons. Antennae short and terete, scape approximately 1.4× greatest width, pedicle approximately 1.7× longer than greatest width (pedicel approximately 1.4× length of scape).

Pronotum broad (Fig. 1A), 2× longer than vertex at midlength, tricarinate, lateral carinae laterally arched, not reaching posterior margin; in lateral view pronotum declinate anteriorly. Mesonotum approximately 1.5× longer at midlength than vertex and pronotum combined; tricarinate (carinae strong anteriorly), lateral carinae diverging posteriorly, all carinae obsolete (or nearly so) before posterior margin. Calcar about 0.6× length of basitarsus (Fig. 2).

Male terminalia in lateral view (Figs 3A–B) with pygofer broad, irregularly triangular (broadest ventrally), lateral margins of pygofer opening irregularly convex (not strongly produced); medioventral portion of opening from caudoventral view (Figs 3D–E) bearing median flange with elongated spatulate median process flanked with rounded lateral lobes (much wider than tall). Gonostyli (Figs 3D, 4C) strongly sclerotized, forked with basal angle prominent, converging in proximal half (in contact medially), then diverging to blunt apices; outer portion simple, narrowing distad (with a small ridge on inner edge) to broader, spatulate rounded apex. Thecal base (Figs 4A–B) bulbous and twisted, left side bearing a prominent, elongated, helically downcurved process; theca simple and tubular, apex enlarged bearing curved row of fine denticles on apex of left margin, right side bearing a short, acuminate laterally hooked process. Anal tube from lateral view broad, relatively short and quadrate, ventrolateral margins each bearing a short, broad, sclerotized process, widely separated from caudal view with apex irregularly rounding.

US Distribution. USA: AL, GA, NC, SC, TN, VA (Fig. 6; see Table 1 for distribution from the Oriental region).

US Plant Association. Arundinaria gigantea (Walter) Muhl. (Poaceae, Bambusoideae, Fig. 5); presumably also on Arundinaria tecta (Walter) Muhl. and cultivated bamboo.

Remarks. This species is similar to E. distincta and E. infumata in habitus and male genitalia (Huang & Ding 1979, Ding 2006), but can be distinguished by the following: ventral process of pygofer elongate, spatulate at middle (not spatulate in E. distincta and E. infumata); gonostyli nearly straight with a small ridge on inner edge (strongly curved outward in E. distincta and without small ridge in E. infumata); apical process of theca is short (very long in E. distincta).

Intraspecific variation has been recognized in body coloration and the configuration of male genitalia, such as the ventral process of the pygofer, the left process at the base of theca, and the thecal apical process. They are thought to be ecotypes due to geographical or host plant isolation (Ding 2006). As in Japanese specimens illustrated by Asche (1983), some individuals lack a spatulate process on the medioventral pygofer opening.

This species is the most common Epeurysa in Japan as well as in China and Taiwan (Yang & Yang 1986, Ding 2006), and can be found from the plains to the high mountains, often attracted to lights. It is bivoltine in temperate regions, but has more than two generations in warmer regions. Adults overwinter. Adults and nymphs are dependent exclusively on various bamboo species, and thus, the host records from Imperata cylindrica (Mochida & Okada 1971, Park & Lee 2024) are most probably erroneous. Adults and nymphs can be found on the stems and leaves of the host, and eggs are laid in groups inside the leaves.

In the U.S., this species has been collected by sweeping host plants and at lights.

Material examined. USA: ALABAMA, Jefferson Co., Old Rocky Ridge, 33.392645, -86.7731322, 12 Jun 2021, V. Charny (2m, UDCC).

TAIWAN: Kaohsiung City: Kaohsiung, Shanping forest research station, 22.96722°N 120.68722°E, 700 m, 23 Jun 2004, C. H. Dietrich (2m, UDCC). Nantou: Huiseun Forest Area, Meifeng, rt. 14 km 15, 24.095°N 121.17778°E, 2100 m, 15 Jun 2004, C. H. Dietrich (1f, UDCC); Sin Shan Forest Rd., 1 km W jct. rt. 66, 23.91083°N 120.88389°E, 700 m, 11 Jun 2004, C. H. Dietrich (2m, 2f, UDCC); Sun Moon Lake, km 4.5, 23.85611°N 120.94611°E, 800 m, 17 Jun 2004, C. H. Dietrich (1m, UDCC). Taichung City: Dashuidhan Rd., km 43, 24.25611°N 121.01083°E, 2300 m, 18 Jun 2004, C. H. Dietrich (5f, UDCC); Dashuidhan Rd., km 45, 24.26917°N 121.03083°E, 2700 m, 18 Jun 2004, C.H. Dietrich (7f, UDCC); Dashuidhan Rd., km 47, 24.26917°N 121.03083°E, 2700 m, 18 Jun 2004, C. H. Dietrich (1f, UDCC); Rt. 8 km 25, base of Dong Moon Mt, 24.17111°N 120.60861°E, 700 m, 26 Jun 2004, C. H. Dietrich (2m, UDCC). Yilan: Chi-Lan Forest Research Station, 24.59611°N 121.4975°E, 600 m, 08 Jun 2004, C. H. Dietrich (1m, 6f, UDCC); Fushan Forest Research Station, 24.75639°N 121.59611°E, 500 m, 09 Jun 2004, C.H. Dietrich (3m, UDCC).

iNaturalist records. USA: ALABAMA: Jefferson Co. (230749500, 215610852, 178393916, 170924232, 170277722, 170277713, 118719823, 124890591, 87990964, 84468536, 84468527, 82538093). GEORGIA: DeKalb Co. (180563180, 180713520, 83261541). NORTH CAROLINA: Durham Co. (227735723); Guilford Co. (128934850); Mecklenburg Co. (95865949); Orange Co. (172437470); Rockingham Co. (220364375); Wake Co. (129097637, 196408976, 237209402, 236830923, 235393539, 231622873). SOUTH CAROLINA: Greenville Co. (135258711, 261210198); Richland Co. (231554592). TENNESSEE: Hamilton Co. (267794804). VIRGINIA: Fairfax Co. (233513763, 233546987).