Hexatoma (Eriocera) stackelbergi Alexander, 1933

Podenas, Sigitas, Park, Sun-Jae, Byun, Hye-Woo & Podeniene, Virginija, 2022, Hexatoma crane flies (Diptera, Limoniidae) of Korea, ZooKeys 1105, pp. 165-208 : 165

Hexatoma (Eriocera) stackelbergi Alexander, 1933

Figs 47-49 , 65

Hexatoma (Eriocera) stackelbergi Alexander 1933: 152-153, pl. 1, fig. 14; Savchenko 1983: 67 (short note on distribution); 1989: 123 (short note on distribution); Podeniene and Gelhaus 2015: 104-107 (descriptions of larva and pupa), figs 29-38.

Type material examined.

Paratype, male (antenna, fore leg, and both wings slide-mounted), Russia, E. Siberia, Ussuri, Tigrowaja, Suchan distr., 43°15.00'N, 133°00.00'E, [alt. 250 m], 11 June1927, Stackelberg leg. (USNM).

Other examined material

(Fig. 65 ). North Korea, 1 female (pinned, fragments of ovipositor in microvial on same pin), Kankyo Nando Puksu Pyaksan , alt. 1830 m, 29 July 1939, A. Yankovsky leg. (USNM) .

Description.

Body coloration brownish gray (Fig. 47 ). Body length of female 8.8 mm, wing length 10.4 mm.

Head. Gray, Brownish gray anteriorly, pale gray posteriorly, covered with short whitish erect setae. Vertical tubercle large, divided by medial grove longitudinally. Eyes widely separated, distance between them at base of antennae approximately equals to length of scape. Basal segments of antenna brown. Scape elongate, 1.6 × longer than wide, 2.7 × as long as pedicel, darker at base, dusted with gray. Pedicel short, subglobular. Basal flagellomere 1.6 × longer than scape, nearly cylindrical, second flagellomere 0.6 × as long as basal. Flagellomeres covered with short semi-erect whitish pubescence. Rostrum very short, dark brown, palpus black, labella pale brown.

Thorax. Cervical sclerites pale brown, dusted with gray. Pronotum much wider than long, yellowish brown with gray dusting. Prescutum and presutural scutum gray with three darker brown longitudinal stripes and covered with sparse short whitish setae. Medial stripe separated longitudinally by narrow darker line. Tubercular pits missing, pseudosutural fovea small, pale brown. Postsutural scutum with each lobe gray with indistinct darker brownish spots anteriorly, at middle and posteriorly. Scutellum brownish or yellowish gray with longer yellowish setae along posterior margin. Mediotergite brownish gray, more brownish posteriorly. Pleuron gray with brownish spots where gray pruinosity scarcer. Laterotergite with dense long yellowish setae posteriorly. Wing (Fig. 48 ) slightly iridescent, subhyaline, with pale grayish tinge, yellowish in costal area and at base. Stigma missing except darkening around R1 and R2. All veins surrounded by brownish, but no other spots. Veins brown, yellowish at wing base, except distinctly dark brown axillary vein. Macrotrichiae on distal veins missing. Venation: humeral vein slightly before arculus, Sc long, reaching wing margin slightly beyond branching point of Rs, sc-r at or slightly before branching point of Rs. Rs long, slightly arched, short spurred at base in paratype. Free end of R1 short and oblique, R2+3 just slightly exceeds R2 in length. R3 and R4 diverging, ~ 2.5 × as long as its stem. Cross-vein r-m distinct, in alignment with basal deflection of M1+2 (base of discal cell). Discal cell slightly more than twice as long as wide. Cross-vein m-cu very slightly beyond base of discal cell (branching point of M). Vein CuP curved at distal part, thus cell cua gets wider towards wing margin. Anal vein long, slightly sinuous, reaching wing margin slightly before or at same level as Rs base. Anal angle wide, posterior margin widely rounded. Halter with stem and knob yellow, base of stem brownish. Length of female halter 1.2 mm. Coxae brown anteriorly, grayish yellow posteriorly, covered with short erect whitish setae. Trochanters obscure yellow. Femur with basal half pale yellow, distal brown. Tibia and tarsus brown to dark brown. Tibia of posterior leg with two apical spurs. Female femur I: 3.0 mm long, III: 5.5 mm, tibia III: 8.0 mm, tarsus III: 3.5 mm. Claw yellowish at base, blackish at apex, with subbasal spine.

Abdomen. Tergites brown, dusted with gray, with one pair of transverse sutures, covered with short yellowish setae. Sternites yellowish brown. Male hypopygium large, black, epandrium wider than long, polished black ( Alexander 1933). Ovipositor yellowish brown. Spermatheca (Fig. 49 ) brown with small paler dots, ovoid.

Elevation range.

Above 1800 m in Korea, ca. 250 m in Russia.

Period of activity.

Late August in Korea, middle of June in the Far East of Russia.

Habitat.

Unknown in Korea. Larvae of this species develop in the bottom gravel of large and medium size rivers. Last instar larvae and pupae can be found in the riparian zone, usually in gravel, sand or under stones in Mongolia ( Podeniene and Gelhaus 2015).

General distribution.

Far East of Russia and Mongolia. Recorded on the Korean Peninsula for the first time.

Remark.

Hexatoma stackelbergi was known only from three type specimens, all males, listed in Alexander (1933). The male genitalia were not illustrated and we had no possibility to study them. This is the first record not only for Korea, but it is also the first specimen besides the types and the first female. Unfortunately, it has badly damaged terminalia, thus a more detailed study of the ovipositor is not possible at this time.

Figures

Figures 47 - 49. Hexatoma (Eriocera) stackelbergi Alexander, 1933 47 female, lateral view 48 female wing 49 spermatheca. Scale bars: 1.0 mm (47, 48); 0.1 mm (49).

Figures 59 - 66. Sampling localities of Korean Hexatoma (Eriocera) 59 H. (E.) gifuensis Alexander, 1933 60 H. (E.) ilwola sp. nov. 61 H. (E.) masakii Alexander, 1934 62 H. (E.) pernigrina Alexander, 1938 63 H. (E.) pianigra sp. nov. 64 H. (E.) serenensis sp. nov. 65 H. (E.) stackelbergi Alexander, 1933 66 H. (E.) ussuriensis Alexander, 1934.