Piezura nigrigenus Nishida, 1975

Moores, Amy & Savage, Jade, 2005, A taxonomic revision of Piezura Rondani (Diptera: Fanniidae), Zootaxa 1096 (1), pp. 41-59 : 52-53

3. Piezura nigrigenus Nishida, 1975

Figs. 3A–B

Piezura nigrigenus Nishida, 1975: 21

Diagnosis: Frons at narrowest point 2.2x width of first flagellomere, postpronotum yellow, hind tibia with av absent, mesolobus with a pointed apex ( Fig. 3A ). Known only from Japan, female undescribed.

Type material examined: Paratype ♂ labeled Mt. Funagata / Miyagai / Japan / 21 June 1971 / Coll. S. Shinonaga ; Paratype; Piezura nigrigenus / Nishida / Det. K. Nishida ( NSMT) .

Description:

Male: body length 5.1–5.3 mm.

Head: Background color dark brownish­gray; frons at narrowest point 2.2x width of first flagellomere; frontal vitta brown, reddish anteriorly; anterior fronto­orbital plate with 4–5 medioclinate fr and with a few setulae; 1 reclinate upper orb, lower orb absent; parafacial silver pollinose; fronto­orbital plate steel­gray; first flagellomere 2.3–2.8x as long as wide; scape, pedicel and base of first flagellomere yellow, distal half of first flagellomere dark grayish­brown; arista short plumose, with longest hair 0.6x width of first flagellomere.

Thorax: Background color brownish gray; three golden brown dorsal vittae present, median one broader than lateral ones; anterior presutural dc 0.3–0.5 length of posterior presutural dc; presutural acr triserial, postsutural acr irregular; scutellum with 1 strong ap sctl, 1 weak ds sctl, 2 b sctl, the anterior one weaker, 2–3 accessory discal setulae; postpronotum yellow.

Legs: Apex of all femora slightly infuscated; t2 with 1 ad on apical third; t3 with av absent, 1 ad on apical half, 1 d on apical half, 1 preapical d, a few erect setae present on apical third of pv surface; f3 with 1 row of short av, with 1–4 stronger av on apical third, 1 row of ad, stronger towards apex, 1 preapical d, 1 preapical ad and 1 row of short pv with 1–4 stronger pv on apical third.

Wings: Costal spine inconspicuous, no more than 1.0–1.3x length of surrounding costal setulae.

Abdomen: Tergites 2, 3 and 5 reddish yellow, tergite 4 completely darkened; tergites 3 and 5 laterally darkened, both with a dark median vitta.

Postabdomen: Mesolobus approximately 2x as high as wide with pointed apex ( Fig. 3A ); sternite 5 4x as wide as long, weakly V­shaped ( Fig. 3B ).

Female: unknown

Distribution: PALAEARCTIC – Asia: Japan.

Remarks: Piezura nigrigenus is very similar externally to P. nearctica , but the shape of the mesolobus ( Fig. 3A for P. nigrigenus and Fig. 2A for P.nearctica ) is quite distinct in these species.

Figures

FIGURE 2. Piezura nearctica Chillcott. A. Male genitalia external structures, posterior. B. Female spermatheca. C. Female genitalia, ventral. D. Male sternite 5, ventral.

FIGURE 3. Piezura nigrigenus Nishida. A. Male genitalia external structures, posterior. B. Male sternite 5, ventral.