Zanchius undetermined

Zanchius sp. Figs 1 D – F, 3 C – D Specimen examined. 1 ♀ Vietnam • Hoa Trung Lake, Hoa Lien Ward, Hoa Vang District, Da Nang City, 16.0891°N, 108.0425°E, 90 m altitude, on Mallotus barbatus, 2.xi.2024, J. Kim (ZCDTU) (DTUHMM 0022); 3 ♀♀ Vietnam • same location as for holotype, on Mallotus barbatus, 7.xi.2024, J. Kim (ZCDTU) (DTUHMM 0041–0043). Description. Female: coloration: head: entirely yellowish pale brown, except for the greenish posterior margin of head; antennae mostly light brown, slightly tinged with red-orange; first and second segments entirely light brown, slightly tinged with red orange; third and fourth segments brown, somewhat fuscous; labium greenish brown. Thorax: pronotum mostly green with medial pale marking; scutellum green, lateral areas and apex pale; hemelytra mostly green with pale parts; clavus mostly green, apical part pale; corium mostly green, posteroinner part pale, posterior part of embolium pale, with cell-like, green, oval margin; cuneus subhyaline, lateral margin green; membrane subhyaline, tinged with green basally; legs partly green and pale brown; femur mostly green; bluish-green stripe at lateral margin; tibia and tarsus entirely pale brown, except for dark claw. Abdomen: entirely green. Surface and vestiture: body somewhat glossy, sparsely covered with long, silvery setae; head smooth; frons and clypeus densely covered with silvery setae; antennae densely covered with short, dark, erect setae; pronotum smooth, covered with setae in lateral margins; scutellum smooth; hemelytra covered with silvery setae; corium sparsely covered with silvery setae; lateral margin of embolium densely covered with silvery setae; cuneus covered with silvery setae. Structure: body elongated, length 2.71–2.74 mm. Head: hypognathous, about twice as wide as long; vertex wider than eye; frons protruding forward of compound eye in dorsal view; postocular distance shorter than first antennal segment diameter; antennae linear, shorter than body length; first segment thick, shorter than head length, subequal to vertex width; second segment more than 5 times as long as first segment, subequal to third and fourth segments combined; third segment subequal to fourth segment; proportion of first to fourth antennal segments 0.2: 1.1: 0.6: 0.5; labium exceeding hind coxae; proportion of first to fourth labial segments 0.2: 0.19: 0.22: 0.34. Thorax: pronotum trapezoidal, basally twice wider than long, posterior margin sinuate; calli swollen; scutellum and exposed part of mesoscutum large, combined length mesially shorter than wide, longer than pronotum; exposed part of mesoscutum large, slightly as long as scutellum at midline; commissure about twice as long as scutellum; cuneus small, not elongate, cuneal length laterally about one-fourth as long as corial length; hind-leg remarkably long, hindtibia subequal to costal margin. Abdomen: tapered to apex, not reaching to apex of cuneus. Genitalia: sclerotized rings (sr) of dorsal labiate plate roughly triangular (Fig. 3 C); posterior wall with serrate interramal lobe (irl), irl narrow, long, and apically rounded (Fig. 3 D). Host. Mallotus barbatus (Euphorbiaceae). Distribution. Known only from the specimen locality in Vietnam (Central). Remarks. Despite exhibiting distinct external morphology and female genital structures, we have decided to postpone its description as a new species until a male specimen becomes available, to avoid potential taxonomic issues because in most species studied in Zanchius so far, the male genitalia are well described, whereas information on the female genitalia is almost entirely lacking, with only a few species documented. Although the genus Zanchius may be subject to future revision, assigning this species to Zanchius is reasonable based on the currently established definition of this genus. This species is most similar to the Taiwanese Zanchius apicalis Poppius, 1915, but it can be distinguished by small body, approximately 2.7 mm (vs body large, approximately 4 mm); broader head, head length subequal to 1 / 2 head width (vs length more than 1 / 2 width); first antennal segment shorter than 1 / 5 second segment (vs first longer than 1 / 5 second segment); second antennal segment without apical marking (vs second segment with dark apical marking); and entirely green middle part of corium (vs middle part with pale marking) (see Lin 2005: figs 1 A, B, 2 A – C). This species is similar in general shapes of body and head to Zanchius quinquemaculatus, but it can be easily distinguished by body small (vs body large, more than 3 mm), without any colorful spots (vs with remarkable five orange-red spots); second antennal segment shorter than third segment (vs second subequal to third segment); inner part of corium with pale marking (vs inner part entirely green); and vein without any marking (vs vein apically with dark marking).