Nipponomyia Alexander, 1924 Figs 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19

Type species.

Tricyphona kuwanai Alexander, 1913 by original designation in Alexander (1924): pages 158-159.

Descriptive notes on Nipponomyia Alexander, 1924 based on Japanese species.

General coloration yellow to black, with or without conspicuous marking on thorax. Markings of body not differing significantly between sexes.

Head: Rostrum short. Eye appearing bare; however, a few small setae present between ommatidia, near to border of compound eye (Fig. 2A, B). Eyes widely separated. Antenna short in both sexes, only little longer than head. Scape 1.2-1.4 × longer and wider than pedicel. Pedicel 1.8-2.2 × wider than first flagellomere. Flagellum 11-13-segmented, evenly narrow toward apical segment. Flagellomeres oval to cylindrical, first 9 or 10 flagellomeres with 1 or 2 long, erected verticils dorsally (Fig. 2C, D). Last 3 or 4 flagellar segments with 3 or 4 verticils arranged irregularly. Last flagellar segment with 3 or 4 dark apical verticils, slightly curved upward, differing in shape to other verticils. Ventral part of flagellomeres densely covered with whitish sensilla, shorter than diameter of basal segment (Fig. 2E). Additional microtrichia on flagellomere (Fig. 2E). Palpi 5-segmented, length varying among species.

Thorax: Elongated in dorso-ventral direction (Fig. 3A, C). Cervical sclerite elongated fusiform. Pronotum well developed, medial part of antepronotum with hump and long setae; antepronotal lobe well developed, dorsal part slipping under medial part of antepronotum; postpronotum relative narrow. Prescutum with anterior part rounded, greatly protruding anteriorly, above to the pronotum in lateral view. Scutum usually with conspicuous spots. Presutural area of scutum without longitudinal suture, just with solid line of some long hairs (Fig. 3D); area under line of hairs before transverse suture bare in SEM photo ( N. trispinosa) (Fig. 3D); not evident under stereomicroscopes. Transverse suture deep, V-shaped, generally with dark patch in middle. Mediotergite elongated, dorsal margin almost straight in lateral view (Fig. 3A, C). Episternum, epimeron, and laterotergite each virtually not divided. Pit between episternum and epimeron deep (Fig. 3C). Meron relatively small, narrow in middle, forming two triangular parts, ventral one bigger. Metepisternum angular, additional divisions indistinct.

Legs: Longer in male than in female. Fore coxa elongated, extending ventrally beyond episternum. Tibia longest segment in both sexes. Male fore tarsomere 1 as long as fore femur or slightly longer. Tibial spur formula: 1, 2, 2, spurs just half length of width of tibia. Tarsomeres with 2 spurs. Male tarsomere 5 shorter than tarsomere 4. Female tarsomere 5 longer than tarsomere 4. Tarsal claw simple, without teeth, covered with small hairs on base, arolium present (Fig. 3E). Average relative lengths of each segment (in percentage %) to the total length of corresponding leg (100%) listed in Table 1 for both sexes.

Wing: General wing venation as in Fig. 4A. Longitudinal veins with setae; crossveins bare. Sc long, ending beyond fork of Rs. Crossvein sc-r before origin of Rs and before or on same level as A2. Usually Rs forking into R2+3+4 and R5 (Fig. 4A-D, F) or rarely into R2+3 and R4+5 (Fig. 4E, G); highly variable within species. Crossvein r-m before fork of Rs, except in N. khasiana Alexander, 1936. R1 and R3 approaching each other at position of R2. Cell r4 wider at middle. Usually cell d closed, longer than cell m2. Direction of crossvein m-m variable, usually almost perpendicular (Fig. 4A-E, G) or oblique (Fig. 4F). Anterior margin of wing with yellow band, bordered with different sized and shaped brown-black patches. Additional transverse markings (dashes, dots) in costal cell present in some species (Fig. 4B-E). Additional brown markings along veins, from fork of Rs to m-m and to m-cu (Fig. 4F, G).

Abdomen: Covered with relative long and dense hairs. Membranous area of second sternite well developed, shaped as in Fig. 3A, B. Usually tergites and sternites each with longitudinal dark line on lateral side (Figs 8B, 10B, 14B, 15B, 18B) and/or with spots and transverse lines (non-Japanese species).

Male terminalia: Relatively simple. Tergite 9 (epandrium) and sternite 9 (hypandrium) fused; border indistinct, forming wide ring, bulging in ventral side (Figs 5E, F, 11E, F, 16E, F, 19E, F). Tergite 9 simple without any lateral projections/arms. Gonocoxite well developed, stout, membranous on inner side. Basal lobe on ventral side of gonocoxite variable in size among species. Apical lobe of gonocoxite (sometimes referred to as outer gonostylus) partly separated from gonocoxite, elongated and directed dorso-ventrally, covered with short dark spines (Fig. 5A, B, G, H). Interbase long, well developed, fused with gonocoxite (Fig. 5G, H), with a few pale setae on ventral side. Gonostylus with two parts (Fig. 5B); inner (anterior) part of gonostylus always elongated, directed inwards; outer (posterior) part of gonostylus always shorter, wide (Figs 5G, H, 11G, H) or slender (Figs 16G, H, 19G, H) bearing 2-14 black spines. Aedeagus complex simple in shape as in most species of Pediciidae; difference among species more distinct in lateral view (Figs 5I, J, 11I, J, 16I, J, 19I, J). Aedeagus complex fused with sternite 9; relatively hard to separate from it; fused part referred in this article as aedeagal guide. Shape and length of aedeagus variable among species.

Female terminalia, ovipositor: Elongated, tergites 8-10 fused (Fig. 6A, B). Pair of small pits situated between tergites 8 and 9. Tergite 8 at least twice as wide as tergite 9 in lateral view. Cercus longer than combined length of tergites 8-10. Cercus almost straight (Fig. 12C, E) or curving dorsally (Figs 6B, 12A). Hypogynal valve dorsally with 5-7 strong setae pointing caudally, terminal seta well separated from penultimate one and situated laterally to anterior setae (Fig. 6B, C). Genital fork well-developed, spoon-like or cruciform. Pair of membranous invaginations ("interbase sheath") present on ventral side of genital fork, holding interbases during copulation (Fig. 7B). Sternite 9/genital plate with two sclerites lateral of genital fork, variable in shape and development among species and even within species (Figs 7A, B, 12B, D, F). Pair of sclerotized (darker) area between genital fork and genital opening present in some species. Area around genital opening sclerotized, T- or Y-shaped; Three small, light brown spermathecae closely situated to genital opening (Figs 6D, 7C). Sternite 10 rounded apically, with 5-10 longer hairs (Figs 6D, 7B, 12B, D, F).

Larva: Unknown.

Pupa: Unknown.

Distribution.

Eastern Palearctic and Oriental (Fig. 1).

Biology.

Adults swarm in the air close to the ground or above the vegetation, in shadow and windless conditions. They rest on ventral surfaces of substrates like leaves, spreading their wings horizontally, even during copulation. Nipponomyia kuwanai and N. trispinosa males walk fast on the vegetation and fly short distances to find females. Nipponomyia kuwanai females were observed ovipositing in muddy, wet soil, near mosses on a mountain lakeshore. A N. trispinosa female was observed searching for oviposition sites around wet soil, rich of organic matter next to a waterfall, but the oviposition has not yet been observed. Sometimes N. kuwanai, N. trispinosa, and N. pentacantha inhabit the same habitat.