Diplonevra peregrina (Wiedemann, 1830)

(Figs. 2I–L, 3, 4S –U, 5K, 5L, 7E, 7F, 9E, 9F)

Trineura peregrina Wiedemann, 1830: 600 . Type locality: Canton (Guangzhou, China).

Diploneura peregrnia: Schmitz, 1929: 13 (unjustified emendation).

Phora sinensis Schiner, 1868: 224 . Type locality: Hong Kong (synonymy).

Phora conventa Brues, 1911: 535 . Type locality: Takao (Kaohsiung, Taiwan) (synonymy).

Dohrniphora setitibia Malloch, 1925: 333 . Type locality: Sydney, Australia (synonymy).

Diplonevra rubiginosa Michailovskaya, 1990: 696 . Type locality: Ussuriysk, Russia (synonymy).

Diagnosis. This species can be distinguished from other Diplonevra species by the combination of the following characteristics: body mostly yellowish brown with dark brown markings on apical end of hind femur and abdominal tergites; inner face of male hind trochanter with numerous short setae on ventral margin; ventrobasal area of inner face of male hind femur with two peg-like, stout setae and several hairs; hind tibia with two dorsal longitudinal setal palisades, 2 or 3 anterodorsal setae, and 2–4 short anteroventral setae (mostly three anterodorsals and three anteroventrals); wing vein M 1 almost straight but slightly sinuate; hypopygium flattened laterally.

Description. Male. Body length 2.28–3.56mm (n=10). Head (Fig. 2I). Frons orange to yellowish brown except ocellar area dark brown, shiny. Flagellomere 1 yellowish brown, as large as about one-sixth of compound eye, subglobose, slightly pointed apically. Arista brown. Palpus yellow, as wide as maximum width of flagellomere 1, with six bristles and one short seta apically, and some short hairs ventrally. Labrum and labella pale yellow. Thorax (Fig. 2J). Scutum and scutellum orange to yellowish brown. Scutum usually without patterns, but occasionally with three dark brown longitudinal stripes fusing at posteromedial margin of scutum and marginal pattern in some darkcolored specimens (Fig. 3A). Posterior margin of scutum with 3 or 4 (mostly 3) pairs of long prescutellar bristles; inner 2 or 3 pairs shorter and weaker than outermost one pair. Scutellum with two pairs of long bristles of subequal length; anterior scutellar bristles convergent; posterior scutellar bristles apically crossing each other. Pleuron (Fig. 2I) yellow. Legs (Fig. 2I) yellowish brown except brown mid-, hind tarsi and dark brown apical end of hind femur. Fore tibia with single strong dorsal seta on basal half and one row of dorsal short setulae on apical half. Midtibia (Fig. 4S) with two dorsal longitudinal setal palisades; anterodorsal one extending three-fourths of midtibial length while posterodorsal one extending entire length of midtibia. Both of two dorsal midtibial bristles protruding at basal one-fifth of midtibia. Inner face of hind trochanter (Fig. 7E, F) with numerous short setae on ventral margin. Ventrobasal area of inner face of hind femur (Fig. 7E, F) with two peg-like stout setae and several hairs. Hind tibia (Fig. 4T, U) with two dorsal longitudinal setal palisades, 2 or 3 anterodorsal setae, 2–4 short anteroventral setae (mostly three anterodorsals and three anteroventrals), and one row of posterodorsal fine setae. Wing (Fig. 5K). 1.85–2.88mm long (n=10). Costal index 0.47–0.49. Mean costal ratio 7.3:2.2:1; range 6.0–8.0:1.8–2.7:1. Costal setae of costal section III 0.03–0.06mm long. Vein of costal sections II–III not thickened. Base of Rs with single short hair. Vein M 1 almost straight. Vein brown and membrane hyaline with yellow tinge. 2–5 (mostly 4) alular setae present, 0.08–0.13mm long. Halter pale yellow. Abdomen (Fig. 2I, J). Tergites yellow with brown markings; posterior margin of tergite 1 brown; posterolateral margin of tergite 2 and lateral margins of tergite 3–5 with dark brown markings; tergite 6 with dark brown marking posteromedially. Size of dark brown markings on tergites variable (Figs. 2J, 3A). Venter of abdomen pale yellow. Hypopygium (Fig. 9E, F) dark brown, flattened laterally. Epandrium mostly without hairs, dark brown. Left side of epandrium (Fig. 9E) with epandrial lobe not distinctly protruded, bearing one short seta apically. Right side of epandrium (Fig. 9F) with one short seta and some minute, fine hairs posteriorly, and minute, hooked lobe curved inside on posteroventral corner. Hypandrium tomentose. Left plate of hypandrium (Fig. 9E) oval. Right plate of hypandrium (Fig. 9F) with rounded posterior margin. Cercus with one pair of pale yellow sclerites mounted dorsally on pale yellow stalk; length of cercus five times as long as maximum width of cercus; stalk with numerous long hairs but absent on basal one-fourth.

Female. Body length 3.45–5.30mm (n=8). Head (Fig. 2K) similar to male, except flagellomere 1 smaller, palpus broader with 7 or 8 apical bristles, and labrum robust. Thorax (Fig. 2L) similar to male, with same pattern variations as male (Fig. 3B–E). Legs similar to male, except without structures on inner face of hind trochanter and femur. Wing (Fig. 5L) similar to male, 2.59–3.68mm long (n=8). Costal index 0.49–0.53. Mean costal ratio 7.3:2.3:1; range 6.1–8.6:2.0–2.7:1. Costal setae of costal section III 0.03–0.08mm long. Four alular setae present, 0.10–0.17mm long. Halter pale yellow. Abdomen (Fig. 2K, L). Tergites present only on abdominal segment 1–4 and 9. Tergite 1 yellow, fully developed. Tergite 2 yellowish brown to orange, fully developed, with one pair of dark brown markings posteromedially. Tergite 3 usually yellowish brown with one pair of dark brown markings posteriorly, 0.6 times as wide as width of tergite 2. Size of dark brown markings of tergite 2 or 3 variable, and tergite 3 entirely dark brown in some dark-colored specimens (Figs. 2L, 3B–E). Tergite 4 small, yellowish brown to grayish brown, various in size and shape (circular, oval, reverse-trapezoid, or wide half-moon shaped) (Fig. 3B–E). Membranous area of dorsal and lateral face of abdominal segments 1–7 grayish brown. Venter of abdomen pale yellow to grayish yellow. Abdominal segment 8 membranous, grayish brown, with short hairs dorsally and longer hairs ventrally. Abdominal segment 9 yellow, flattened, tapering apically; tergite 9 with median ridge bearing one pair of long hairs posteriorly; sternite 9 with erected short hairs on surface. Cercus yellow, rounded, with two long hairs apically.

Specimens examined. South Korea: 1♂, Incheon, Bupyeong-gu, Cheongcheon 1-dong, Incheon Butterfly Park, 37°31′12.4″N, 126°41′33.2″E, 1–14.v.2012, Malaise trap, M. S. Koh leg. (KNU); 1♂, Gyeonggi-do, Uijeongbu-si, Millak-dong, near Mt. Soribong, 37°45′02″N, 127°08′33″E, 15.vii.2014, Malaise trap , KNA leg. (KNU) ; 1♂, Gyeonggi-do, Pocheon-si, Soheul-eup, Korea National Arboretum, 37°45′22″N, 127°09′48.9″E, 15.ix.2014, Malaise trap , KNA leg. (NIBR) ; 1♂ 1♀, Gyeongsangnam-do, Jinju-si, Ibanseong-myeon, Daecheon-ri, Gyeongsangnamdo Arboretum, 35°09′39.7″N, 128°17′41.3″E, 1–15.vi.2015, Malaise trap , J. H. Hwang leg. (KNU); 1♂, Jeju Is., Jeju-si, Hallim-eup, Ongpo-ri, house near Hyeopjae Beach, 33°23′51.4″N, 126°15′04.1″E, 03–29.vi.2018, Malaise trap , S. Nam leg. (KNU); 1♀, Gyeonggi-do, Yeoncheon-gun, Cheongsan-myeon, Jangtan-ri, wall of artificial building, 38°01′37″N, 126°04′35″E, 21.vi.2018, hand collecting , J. H. Lee leg. (KNU); 1♀, Jeollanam-do, Gwangyang-si, Ongnyong-myeon, Chusan-ri, Southern Experimental Forest of Seoul National University in Mt. Baegunsan, 35°01′52.9″N, 127°36′24.8″E, 15–30.vii.2019, Malaise trap , Nam & Park leg. (KNU); 1♂, Busan, Seogu, Seodaesin 4-dong, near public restroom located in Mt. Gudeoksan, 35°07′39″N, 129°00′21.9″E, 26–29.v.2020, Malaise trap, J. H. Sohn et al. leg. (KNU) ; 1♂, Daejeon, Yuseong-gu, Seongbuk-dong, near Mt. Gyeryongsan, 36°18′52.6″N, 127°17′23.3″E, 13.vi–4.vii.2020, Malaise trap , Oh & Park leg. (KNU); 1♂, Jeollabuk-do, Wanjugun, Gui-myeon, Wongi-ri, near Jeonbuk Museum of Art, 35°43′45.8″N, 127°06′24.8″E, 26.vi–13.viii.2020, Malaise trap, J. H. Sohn et al. leg. (KNU) ; 3♂, Chungcheongnam-do, Seocheon-gun, Pangyo-myeon, Sangjwa-ri, near Jongcheon Reservoir, 36°08′27″N, 126°39′20.7″E, 8.vii–6.viii.2020, Malaise trap, J. H. Sohn et al. leg. (KNU) ; 1♂, Chungcheongbuk-do, Chungju-si, Salmi-myeon, Jaeogae-ri, periodically inundated grassland near Chungjuho Lake, 36°56′01.1″N, 128°00′15.6″E, 17.vii.2020, pitfall trap , D. H. Kim leg. (KNU); 1♀, Gyeonggi-do, Pocheon-si, Soheul-eup, Jikdong-ri, on decaying organic matter at streamside in Mt. Jugyeopsan, 37°46′56″N, 127°10′07.6″E, 18.viii.2020, hand collecting , J. G. Lee leg. (KNU); 1♂, Gangwon-do, Chuncheon-si, Toegye-dong, in convenience store next to Namchuncheon Metro Station, 37°51′51.5″N, 127°43′25.8″E, 6.v.2021, hand collecting , J. H. Lee leg. (KNU); 1♂ 3♀, Gangwon-do, Chuncheon-si, Hyoja-dong, Kangwon National University, behind the building of College of Agriculture and Life Sciences, 37°52′19.1″N, 127°44′44.9″E, 12–27.v.2021, mouse carrion bait trap , S. Kim leg. (KNU); 1♀, ditto (NIBR) .

Ecology. This species is the most common Diplonevra species and is widely distributed in South Korea. The species is usually found in damp conditions such as streamside in deep forest and periodically inundated grassland near lakes or reservoirs. Some adults can be found in artificial areas and urban habitats such as public restrooms and convenience stores. Adults (especially females) are attracted to decaying organic materials such as streamside detritus and vertebrate carrion. In adjacent countries, larvae of this species feed on dead bats in Malaysia (McClure et al. 1967) and rotten pork in Japan (Mitsui & Nakayama 2012). Also, this species is common indoors in China and has been considered a forensically important species for indoor crime scenes because of its necrophagous habits (Feng & Liu 2012).

Distribution. Korea (new record, widely distributed in South Korea), Russia (Far East), Southeast Asia, China, Taiwan, Japan, Pacific Islands, Australia.