Male (Fig. 1A)

Figure 1.  

Hypocharassus cavitarsus sp. n. A male, lateral view; B female, lateral view; C male antenna, lateral view; D male wing, lateral view; E male fourth and fifth sternite, ventral view; F male fore tarsus, dorsal view; G male mid tarsus, dorsal view; H male hind tarsus, dorsal view. Scale bars: A-B and D = 1 mm; C, E-H = 0.5 mm.

Head inverted triangle-shape at anterior view and metallic bluish green with thick whitish pruinosity; vertex slightly concave; ocellar triangle convex; 3 ocellus present; ocellar seta almost straight and divergent and as long as distance between median ocellus and lateral ocellus; postoceller almost straight and approximately 0.5 times shorter than ocellar seta; vertical seta proclinate and approximately 0.5 times shorter than ocellar seta (rarely absent in some specimens); postvertical seta proclinate and convergent and approximately 1–2 times longer than ocellar seta; frons broadened upwards; width between frons and face as long as compound eye at anterior view; face slightly broadened downwards; clypeus subparallel downwards and apically round; compound eye with tiny pale setulae between facets; upper postocular setae black in a single row; lower postocular setae pale and combined with occipital setae; upper occiput flat; lower occiput with thick pale setae; antenna black; scape bare; pedicel setose at apical margin; postpedicel check mark shape and ventral projection 2/5 times shorter than dorsal projection; arista-like stylus thick and two segmented and apical segment minutely longer than basal segment and placed apically; palpus basally grey and apically yellow with pale setulae; proboscis large and black with pale setulae (Fig. 1C).

Thorax metallic bluish green with thick whitish pruinosity and mainly black setae; mesonotum with violet vittae between acrostichal and dorsocental setae starting from anterior scutum and then fading before reaching the scutellum; 3–16 tiny acrostichal setae irregularly biseriate; 14–18 dorsocentral setae tiny, except the long last one; postpronotal lobe with 1 (rarely 2) seta and some pale setulae; 3–5 tiny intra-alar setae, 1 (rarely 2) presutural supra-alar, 3 postsutural supra-alar, 1 (rarely 2) notopleural, 1 postalar setae present; posterial scutum round; scutellum approximately 0.5 times shorter than width and apically round; 2–3 (rarely 4) scutellar setae present and as long as length of scutellum and laterals slightly smaller than median seta; proepisternum with pale setulae; anepisternum, katepisternum, anepimeron, katepimeron, meron and laterotergite bare.

Legs mainly metallic bluish green with thick whitish pruinosity; all coxae and trochanter with pale setulae; fore femur and mid femur with pale setulae and 1 apical posteroventral seta, except black dorsal setulae at apical half; hind femur with black dorsal and pale ventral setulae and 1 apical anterodorsal and 1 posteroventral seta; all tibiae with 1–3 anterodorsals and 1–3 posterodorsal setae and apical ring of setae; all tarsi with 2 long ventral setae at apex of tarsomeres 1–4, respectively; tarsomere 1 grey and almost same or slightly shorter than total length of tarsomeres 2–5; tarsomeres 2­–5 basally yellow and apically grey; fore tarsomere 4 with anterior projection and 2 setae at apex; fore tarsomere 5 anteriorly crooked and gradually widened towards apex and with anterior projection at base; mid tarsomeres 4 and 5 gradually broadened towards apex; mid tarsomeres 5 cone-shaped; hind tarsomeres 4 and 5 slightly broadened towards apex, but less broad than mid tarsomeres 4 and 5; all claws long, approximately twice longer than pulvillus; basal half of fore anterior claw broad, almost equal to width of pulvillus; all empodium pale, narrow feather shaped and curved upwards; pulvillus greyish brown (Fig. 1F-H); length of tibia and tarsus of fore leg (mm), 1.59 : 0.65 : 0.16 : 0.13 : 0.8 : 0.31; mid leg, 1.81 : 1.15 : 0.29 : 0.27 : 0.19 : 0.34; hind leg, 2.31 : 1.34 : 0.36 : 0.32 : 0.26 : 0.36.

Wing simple and hyaline with dark brown veins; C ending at M₁; Sc combined at half of R₁; R₂₊₃ and R₄₊₅ slightly diverging towards wing tip; R₄₊₅ and M₁ divergent before dm-m, then slightly convergent towards wing tip; r-m crossed at branching point of R₂₊₃ and R₄₊₅; M₄ fold-like at wing tip; dm-m straight; CuA+CuP fold-like and ending before reaching wing tip; alula absent (Fig. 1D); calypter pale yellow with pale setulae; halter pale yellow with brown base.

Abdomen metallic bluish green with whitish pruinosity; tergum with black setulae, except lateral pale setulae; sternum with pale setulae; sternite 1 membranous, except lateral small sclerotised apex; sternite 4 with small spikes at posterior median apex; sternite 5 medially concave and membranous (Fig. 1E); epandrium dorsally broad, slightly broader than height; hypandrium fused to epandrium; epandrial lobe bacilli form, approximately 2.5 times as long as width; inner surstylus dorsally crooked bacilli form; outer surstylus dorsally broad with inner projection; phallus narrow and slightly crooked to venter at apex; cerci fused together and forming a trident shape (Fig. 2).

Figure 2.  

Hypocharassus cavitarsus sp. n. male. A genitalia, lateral view; B ditto, ventral view; C ditto, dorsal view. Scale bars: A-C = 0.1 mm. Abbreviations: cer = cercus; epd = epandrium; hyp = hypandrium; i sur = inner surstylus; o sur = outer surstylus; phal =phallus.

Length: body without antenna 5.1–5.3 mm, antenna 0.9–1.0 mm and wing 4.7–5.5 mm.

Female (Fig. 1B)

Almost identical to male, except for the following characteristics: all tarsomeres 4 and 5 only minutely broadened towards apex, fore and mid tarsus without any specific modification like male; sternite 4 without small spikes at posterior median apex; sternite 5 not medially concave and membranous.

Length: body without antenna 5.6–6.1 mm, antenna 0.9–1.0 mm and wing 6.2–6.5 mm.

The species name is derived from a Latin word that translates to concave (cavus) tarsomere 5 of fore tarsus.

Korea (Chungcheongnam-do, Jeollanam-do).