Neochya gen. nov.

Type species.

Atrachya hirashimai Kimoto, 1969

Description.

Coloration: extremely variable but without metallic color. Body length 4.6-7.0 mm.

Head. Labrum trapezoidal, transverse, with six pores in transverse row bearing pale setae, anterior margin medially depressed. Anterior part of head very short, almost impunctate and glabrous, several setae on anterior margin of clypeus and anterofrontal ridge. Interantennal space broad, 1.5-2.6 × as wide as diameter of antennal insertion. Frontal tubercles transverse, subtriangular, slightly elevated, glabrous. Vertex smooth and glabrous. Antennae slender, covered with dense setae, antennomere II as long as antennomere III; similar in both sexes.

Pronotum 1.75-2.00 times as broad as long, lateral margins slightly rounded, basally narrowed. Disc covered with dense, coarse punctures, moderately or strongly convex, with lateral depressions, except N. chengi sp. nov. and N. nitidissima . Anterior margin lacking marginal bead, lateral and posterior margins with marginal bead. Anterior and posterior margins without setae, lateral margins with two pairs of setae near base and apex respectively. Anterior angles moderately swollen, rectangular, posterior angles obtuse angulate, all angles with setigerous pore bearing long pale seta.

Scutellum subtriangular, impunctate, glabrous, with rounded apex.

Elytra ca 1.35-1.68 times as long as wide, almost glabrous (with indistinct, sparse, short, pale setae on humeri, lateral margins and apical slopes), parallel sided, except N. nitidissima (Fig. 9, broader in middle), covered with densely confused punctures. Humeral calli well developed. Epipleura broad at base, gradually narrowed from basal 1/3, abbreviated near apex (Fig. 19D). Macropterous.

Ventral surface sparsely covered with fine punctures and pale setae. Anterior coxal cavities widely open (Fig. 18D). Prosternal process not visible between procoxae. Abdomen simple, posterior margin of last ventrite with two long incisions in males.

Legs slender. All tibiae with one apical spine, the longest spine on metatibia. Protarsomeres I not modified in males. Metatarsomeres I much longer than pro- and mesotarsomeres I, much longer than II and III combined. Claws appendiculate.

Penis broad, with one pair of small lateral processes near apex (Figs 8C-E, 10C-E, 12C-E) (except N. chengi sp. nov. (Fig. 5C-E)); tectum broad, apical margin truncate; internal sac with only one type of endophallic spiculae (median endophallic spiculae).

Gonocoxae (Figs 5F, 8F, 10F, 12F) slender, tightly conjunct medially; each gonocoxa with eight setae from near apex to apical 1/6, subapically widened, apex narrowly rounded, base bifurcate. Ventrite VIII (Figs 5G, 8G, 10G, 12G) weakly sclerotized except apex, with several short and long setae at apex, and several long setae at sides, spiculum elongate. Spermathecal receptaculum (Figs 5H, 8H, 10H, 12H) as slender as pump, apically tapering; pump slender and curved; sclerotized spermathecal duct extremely elongate, but base wide, followed by short slender tube with inflated areas. Bursal sclerites reduced.

Diagnosis.

Neochya gen. nov. differs from Atrachya Chevrolat and Monolepta Chevrolat in the following combination of characters: antennomere II subequal to III in length (antennomere II much shorter than III in Atrachya (Fig. 3A, B)); widely open prothoracic coxal cavities (Fig. 18D) (closed prothoracic coxal cavities in Taiwanese species of Monolepta, Fig. 18C); absence of subscutellar impression on the elytra in males (presence of subscutellar impression on the elytra of Atrachya); penis with tectum broad and apical margin truncate (Figs 5C, 8C, 10C, 12C) (tectum elongate with apex deeply bifurcate in Atrachya (Fig. 3C)), only one type of endophallic spiculae (Figs 5C-E, 8C-E, 10C-E, 12C-E) (three types of endophallic spiculae in Monolepta); gonocoxae slender and subapically broadened (Figs 5F, 8F, 10F, 12F) (gonocoxae broad and parallel-sided in Atrachya (Fig. 3F)), spermathecae with slender receptaculum as pump (Figs 5H, 8H, 10H, 12H) (greatly swollen receptaculum in Atrachya (Fig. 3I)), with apex acute (without acute apex in Atrachya); reduced bursal sclerites (well-developed bursal sclerites in Atrachya (one pair (Fig. 3H)) and Monolepta (two pairs); ventrite VIII with few lateral setae (Figs 5G, 8G, 10G, 12G) (dense lateral setae in Atrachya (Fig. 3F)).

Etymology.

Composed from new and Atrachya to indicate that this is a new genus similar to Atrachya .

Included species.

Neochya chengi sp. nov., N. hirashimai (Kimoto), comb. nov., N. nitidissima ( Chûjô) comb. nov., and N. tsoui sp. nov.