Genus Vitruvius Distant, 1901

Vitruvius Distant, 1901: 111–112 (original description, systematic placement).

Type species: Vitruvius insignis Distant, 1901, by monotypy.

Vitruvius: Distant (1902): 278 (redescription); Bergroth (1908): 186 (catalogue); Kirkaldy (1909): 353 (catalogue); Hoffmann (1932a): 10 (checklist); Kumar & Ghauri (1970): 15, 29 (systematic placement, transferred from Tessaratomidae to Pentatomidae); Hsiao & Zheng (1977): 63 (key to genera); Hua (2000): 170 (placed in Tessaratomidae); Liu & Wang (2004): 176 (key to genera); Rider (2006): 376 (catalogue); Fan (2011): 16 (key to genera), 521 (generic diagnosis); Rider et al. (2018): 110 –111 (morphology, systematic position).

Vitruvinus (incorrect subsequent spelling): He et al. (2011): 59 (plant association, distribution).

Redescription. Body strongly deltoid, widest across humeral angles, slightly flattened dorsoventrally, compact in appearance. General colouration yellowish to brownish, with darker punctures, sometimes forming vague longitudinal bands dorsally, ventrally ochraceous, pale brown.

Head (Figs 4A–C) flat, with semi-circular outline. Mandibular plates extending beyond apex of clypeus, convergent, clearly enclosing clypeus (Figs 4A, C); mandibular plates broad, shallowly concave laterally and clearly covering antenniferous tubercles (Fig. 4A). Lateral margins of mandibular plates slightly deflected upwards. Anteocular tooth absent, however, anteocular region slightly prominent. Eyes globose, protruding from head outline. Ocelli located just behind imaginary line between posterior margin of eyes (Fig. 4A). Bucculae short and low, not covering labrum and labiomere 1, shallowly concave in anterior half, convex in posterior half, its anterolateral angle obtusangulate (nearly rectangular), continually narrowing posteriorly (Fig. 4B). Labium reaching mesocoxae, labiomere 1 reaching posterior margin of head (Figs 4B, C), labiomere 2 longest, labiomere 3 somewhat wider apically, labiomere 4 with apex black. Antennae pentamerous, with scape stout, not surpassing apex of head; length of antennomeres: III and IV (subequal)> IIa and IIb (subequal)> I, basipedicellite (IIa) and distipedicellite (IIb) about 2.5× times as long as scape, basiflagellum (III) and distiflagellum (IV) about 3× as long as scape.

Thorax. Pronotum trapezoidal, clearly broader than long, anterior margin behind head distinctly concave, Ushaped (Figs 1A, 2A, 3A). Anterior angles transversally projected, clearly visible but small, anterolateral margins deflected, anterior margins straight, flattened, uncalloused, with thin black line. Humeri protruding anterolaterad, reaching beyond hemelytral bases. Ventral surface of pronotum evenly punctured, punctures concolourous with surface.Scutellum triangular,elongate;apex narrow,rounded apically; anterolateral angles of scutellum concolourous, slightly foveate (Figs 1A, 3A). Corium slightly convex, laterally lined in black, membrane hyaline, veins clearly marked, concolourous with membrane, with no black or coloured patterns. Apex of membrane somewhat obtuse, flat apically (broadly U-shaped). Coria covering most of connexiva, basal segments partially exposed. Prosternum extremely reduced, neither grooved or ridged (Fig. 4D). Mesosternum with a slightly elevated medial carina; metasternum somewhat elevated medially, very slightly gibbous (Fig. 4D). Ostioles large, oval-shaped, opening ventrally (Fig. 4F); peritreme well developed but short, spout-shaped, only slightly elevated above surrounding pleuron, spatulate apically, its peritremal surface oriented ventrally (Figs 2B, 4E–G). Metapleural evaporatorium large, situated in anterior and central portions of metapleuron, with well developed, sublateral ridge near to its lateral margin (Fig. 4E), distinctly gyrificated (Fig. 4F). Mesopleural evaporatorium extending in posterior and lateral areas of mesopleuron. Legs moderately robust, bearing short, blackish, spine-like setae. Tibiae strongly sulcate, tarsi trimerous, tarsomere II with a protrusion basally near tarsomere III.

Abdomen. Connexiva concolourous with dorsal ground colouration, darker in connexival outline. Ventrolateral sutures between tergites not prominent, last abdominal segment (VII) with posterolateral extension slightly angled, not acute (Figs 1A1, 3A 1). Ventral surface of abdomen evenly punctured except central longitudinal line, which is impunctate (Figs 1A1, 3A 1). Ventral abdominal base wide, with a dorsoventrally flattened tubercle slightly covering and embraced by sternal plates (Fig. 4D). Spiracles black, spiracle on ventrite II partly to almost completely exposed. Trichobothria paired, inconspicuous, located laterally between an imaginary line connecting spiracles and connexival margins, transverse (Figs 5A–B).

Male genitalia. Genital capsule trapezoidal, broader apically near posterolateral angles (Figs 5E–F). Genital cup distinctly exposed dorsally; ventral rim broad; dorsal rim concave with clearly visible, spine-like sclerotized processes on each side of segment X visible in dorsal and caudal views (Figs 1B, 3B: black arrows; 5C–D). Phallotheca dorsoventrally bilobate, basal portion slightly sclerotized; spermathecal reservoir broad, clearly visible (Figs 1C, 3C). Phallus with two pairs of conjunctival processes, internal process bearing a sclerotized hook-like apical portion. Vesica small, inconspicuous. Parameres robust, complex, with a finger-like, small process (Figs 1D, 3D).

Female genitalia. Genital plates broad (Fig 2D); valvifers VIII rounded apically, reduced, partially covered by abdominal segment VII, mesial margins contacting medially, pilose; valvifers IX fused, elongate, trapezoid, internally with a projection on each mesial angle; laterotergites IX rectangular, elongate, pilose, coarsely punctured; sternite X rectangular; laterotergites VIII coarsely punctured, somewhat triangular, with rounded apical angles. Internal genitalia (Fig. 2E): ductus receptaculi elongate, portion before globular vesicular area strongly sclerotized, except basal third. Ring sclerites (rs) elongate oval. Vesicular area membranous, openings not following vesicular axis, slightly displaced laterally. Internal rod of vesicular area strongly sclerotized, parallel-sided, acuminate at base, slightly dilated at apex. When vesicular area is turgid, internal rod of vesicular area bent. Pars distalis less than onehalf length of interior rod of vesicular area. Proximal annular flange developed, projecting transversally, strongly sclerotized. Pars intermedialis robust, basal part in contact with proximal annular flange elongate. Distal annular flange of similar appearance as proximal annular flange, fused to apical receptacle.Apical receptacle elongate, basal portion with a medial expansion, globular-like, constrained at centre, apical part slightly globose, with three, distally directed finger-like projections, one of which clearly surpasses proximal annular flange, the other two shorter (Fig. 2E).

Note. Both species are very similar in external appearance; when specimens of both species are observed simultaneously, however there are some characters that exhibit slight, but constant differences between members of the two species. These differences, however, are difficult to discern without having specimens of both species to compare. Ultimately, the only reliable way to distinguish between the two species is by examining the male genitalia, which are distinctive.

Etymology. The genus was presumably named after Vitruvius, a Roman architect and engineer during the 1 st century BC, known for his ten-volume work titled De architectura. Gender is masculine.