Hexatoma (Eriocera) masakii Alexander, 1934

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) masakii Alexander, 1934

Figs 21-25 , 61

Hexatoma (Eriocera) masakii Alexander 1934b: 48, pl. 1, fig. 18.

Type material examined.

Holotype, male (pinned, antennae, legs and wing slide mounted), South Korea, Suigen, Chosen, 14 August 1930, I. Tabashi leg. (USNM).

Other examined material.

South Korea, 7 males (pinned), #26, Central National Forest , 18 mi. NE of Seoul, 37°44.89'N, 127°17.62'E, alt. 110 m, 14 August 1954, G. W. Byers leg. (SMEK, USNM) .

Description.

Body.Thorax brown, head, and abdomen orange-yellow (Fig. 21 ). Male body length 9.5-11.5 mm, wing length 9.0-10.2 mm.

Head. Orange-yellow, narrowly grayish along posterior eye margin, sparsely covered with short erect brown setae. Vertex with distinct uniformly pale orange-yellow tubercle. Eyes widely separated in male, distance between them at base of antennae nearly the same as length of both basal antennomeres. Male antenna 8-segmented, 16.0-19.5 mm long, ~ 2 × as long as wing (Fig. 21 ). Scape short and wide, approximately as long as wide, 3 × as long as pedicel, nearly cylindrical, brownish yellow, covered with few very short brown setae. Pedicel small, subglobular, brownish yellow. Basal flagellomere very long, cylindrical, pale yellow with narrowly dark brown apex. Second flagellomere brownish yellow, darker at base and apex. Remaining flagellomeres brown. Apical segment elongate, subcylindrical, more than twice as short as preceding. All flagellomeres covered with dense erect whitish pubescence and scattered short dark brown setae, length of which less than pubescence on two basal flagellomeres, slightly exceeds length of pubescence on base of third flagellomere, and 2-3 × longer on remainder of flagellum. Rostrum orange-yellow. Palpus and mouth parts dark brown.

Thorax. Cervical sclerites and pronotum dark brown. Prescutum blackened. Presutural scutum and prescutum semi-polished dark brown, covered with scattered short brown setae and very sparse brownish pruinosity, longitudinal stripes missing. Tubercular pits missing, pseudosutural fovea distinct. Dorsopleural membrane yellow frontally. Postsutural scutum with each lobe blackish, area between lobes polished dark brown. Scutellum brown, sparsely dusted with brownish pruinosity. Mediotergite brown, darkened posteriorly. Pleuron brown, very sparsely dusted with gray. Episternum bare, setoseless, ventral margin of katepisternum blackish. Meron well developed, second and third pairs of legs staying apart. Wing (Figs 24 , 25 ) iridescent, brownish, with brown frontal margin. Brown area extends through costal area, stigma and reaches vein R4. Indistinct darkenings surrounding cord and distal margin of discal cell. Veins brown. Venation: Sc very long, reaching wing margin slightly before branching point of R2+3 and R4, sc-r shortly beyond branching point of Rs. Radial sector long, nearly straight, slightly arched at base. Free end of R1 longitudinal, R2 twice its own length beyond branching point of R2+3 and R4. R3 and R4 slightly diverging at wing margin, cell r3 with long stem, which is twice as long as R2+3. Cross-vein r-m distinct, transverse, at base of discal cell. Discal cell nearly twice as long as wide, sometimes open due to reduction of cross-vein m-m (Fig. 25 ). Cross-vein m-cu at ~ 1/3 of discal cell. Anal vein long, slightly sinuous, apex reaching wing margin slightly before the level of Rs base. Anal angle wide, posterior margin widely rounded. Halter black with pale base. Length of male halter 1.5-1.7 mm. Coxae brown to dark brown, fore coxa yellowish postero-ventrally. Fore trochanter yellowish, middle and hind trochanters yellowish dorsally, brownish ventrally. Femur brownish yellow with pale yellow base and conspicuous black apical ring. Tibia brownish yellow with narrowly infuscate apex. Basal tarsomere brownish with yellow base, remainder of tarsus brown to dark brown or black, covered with long dense dark brown setae. Tibia of fore leg with single apical spur, tibiae of middle and hind pairs of legs with two apical spurs each. Male femur I: 5.2-6.5 mm long, II: 5.0-6.0 mm, III: 5.9-6.0 mm, tibia I: 6.0-8.3 mm, II: 6.4-6.5 mm, III: 7.7-8.0 mm, tarsus I: 7.2-8.5 mm, II: 5.2-6.3 mm, III: 4.5-5.8 mm. Claw simple, without spines.

Abdomen. Abdominal segments orange yellow. Tergite laterally narrowly blackened, with paired transverse suture at ~ 1/3 of length. Sternite with lateral margin narrowly blackened and with longitudinal spot in the middle. Eight sternite without black spot in the middle. Lateral and ventral abdominal lines interrupted at posterior margins of segments. Whole ninth segment compact, making genital ring, yellow dorsally, pale brown ventrally. Male genitalia (Figs 22 , 23 ) brownish yellow to pale brown. Epandrium wider than long, posterior margin with two low wide lobes separated by shallow emargination. Gonocoxite twice as long as wide, slightly wider at base, without additional lobes. Outer gonostylus long and narrow, sclerotized, with sharp apical spine turned mesally, inner margin finely serrated. Inner gonostylus long, fleshy, setose. Paramere with two long narrow arms. Aedeagus simple, short, and straight, apex bifid. Anterior apodeme long and narrow, but extending forward less than lateral margins of aedeagal sheath.

Elevation range in Korea.

Slightly above 100 m.

Period of activity in Korea.

Middle of August.

Habitat.

Unknown.

General distribution

(Fig. 61 ). Endemic to South Korea (erroneously listed for North Korea by Oosterbroek (2022)). May be extinct due to urban development; not one specimen was found in the tens of thousands we collected. However, it is difficult to collect Hexatoma adults: you need to be at the right place and at the right time to catch them or to see them swarming.

Figures

Figures 21 - 25. Hexatoma (Eriocera) masakii Alexander, 1934 21 male, lateral view 22 male genitalia with ninth segment removed, dorsal view 23 male genitalia, dorsal view 24 male wing 25 male wing variation with open discal cell. Scale bars: 1.0 mm (21, 24, 25); 0.5 mm (22, 23).

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.