Piezura Rondani, 1866

Moores, Amy & Savage, Jade, 2005, A taxonomic revision of Piezura Rondani (Diptera: Fanniidae), Zootaxa 1096 (1), pp. 41-59 : 44-46

Genus Piezura Rondani, 1866

Piezura Rondani, 1866: 71 . Type species: Piezura pardalina Rondani, 1866 , by original designation.

Platycoenosia Strobl, 1894: 72 . Type species: Platycoenosia mikii Strobl, 1894 (= Anthomyza graminicola Zetterstedt, 1846 ), by original designation.

Choristomma Stein, 1895: 12 . Type species: Choristomma pokornyi Stein, 1895 (= Anthomyza graminicola Zetterstedt, 1846 ), by monotypy.

Diagnosis: Piezura can be distinguished from other fanniid genera by a plumose or long pubescent arista combined with the presence of three katerpisternal bristles, the median one weaker and located more ventrally than the other two.

Description

Male: body length 4.5–6.0 mm.

Head: Background color dark brownish­gray; holoptic or dichoptic, with frons at narrowest point ranging from 1.0–3.5x width of first flagellomere; frontal vitta usually dark grayish­brown to black, occasionally brown with orange tinge in P. graminicola ; anterior fronto­orbital plate with 2–7 medioclinate fr and a few interspersed setulae; posterior fronto­orbital plate usually with one reclinate upper orb except in P. graminicola where a lower latero­reclinate orb is also present; parafacial pollinose, silver to grayish­ brown; fronto­orbital plate usually darker than parafacial, being grayish­brown pollinose; antenna with scape and pedicel yellow, first flagellomere yellow with grayish to yellowish­brown apex; aristal hairs short plumose, no more than two­thirds width of first flagellomere, except in P. graminicola where they are as long as width of first flagellomere; palpus yellow, slender and tubular.

Thorax: Background color brownish­gray to brownish­black; postpronotum dark or yellow; three distinct dorsal vittae; anterior dc one­half to two­thirds length of posterior dc; pre­sutural acr short and weak, triserial to irregularly quadriserial, post­sutural acr irregularly quadriserial; 2 npl; 3 kepst, middle one weaker, katepisternum with a few accessory setulae; 2 premp, upper one 2x as long as lower; 2 prepst, posterior 2x as long as anterior; scutellum with underside and margins yellow, disk more or less extensively infuscated; 1 strong ap sctl, 1–2 weaker ds sctl, 2 b sctl, anterior weak, 2–3 accessory discal setulae.

Legs: Background color yellow, with apex of femora often more or less extensively infuscated, tarsomeres black; f1 with row of strong pv, weaker basally; t1 with 1 ad on middle third, with 1 strong preapical d, distinct apical v, av, pv; f2 with short dense row of av, becoming crowded apically to form a pre­apical comb, also with short dense mat of pv, more crowded apically; t2 with ventral mat of short dense setae, 1–2 ad on apical third, 1 preapical d, 1 pd on apical third, 1 ad ­d, 2–3 strong apical v; f3 with 1–4 distinct av; t3 with 0–1 distinct av on apical third, 1–3 ad on apical half and with a pre­apical ad; 1–2 d on apical half, 1 preapical d, apical av and apical pv strong.

Wings: Smoky brown; veins yellowish­brown; costal spine weak or strong; Sc and R 1 diverging near the base; imaginary extension of A 2 meeting with imaginary extension of A 1 before wing margin; both calypters pale yellow with lower one extending further posteriorly; halter whitish­yellow.

Abdomen: Background color yellow; weakly tapering toward apex; with or without dark lateral margins; with or without dark median vitta.

Postabdomen: Epandrium approximately as wide as high; mesolobus usually 2x as high as wide when measured at mid­length, except in P. graminicola where it is 1.3x as high as wide, with apex blunt, pointed or bifurcate; surstyli with tapering serrated apex; sternite 5 1.3–3.4x as long as wide with long bristles along the posterior margin and shorter discal bristles.

Female: body length 4.0–7.0 mm. Differs from male as follows:

Head: Frons at narrowest point at least 2.5x width of first flagellomere; upper orb reclinate, lower orb latero­reclinate.

Thorax: As in male

Legs: As in male except: f2 without ventral comb and mat; t2 without pre­apical comb and ventral mat; f3 with a row of 2–3 strong apical av; t3 with 1–2 av on apical half, with or without pre­apical av; 1–2 ad on apical half and 1 pre­apical ad; 1–2 d on apical half.

Wings: As in male

Abdomen: As in male except more strongly tapering towards a pointed apex.

Postabdomen: Ovipositor telescopic; two robust spermathecae, spherical and slightly wrinkled with short and weakly sclerotized duct bases; tergite 6 broad and well sclerotized, with spiracles 6 and 7 located near ventral margin, sternite 6 2x as wide as long, irregularly bristled; tergite 7 similar to tergite 6 but without spiracles, sternite 7 1.5x as wide as long, irregularly bristled; tergite 8 similar to tergite 7 but darker laterally, sternite 8 divided into 2 large anterior plates with no bristles and 2 much smaller and circular posterior plates, each with 3–4 bristles; tergite 10 weakly pointed apically, setulose with stronger marginal setae; sternite 10 weakly pointed apically, setulose with stronger posterior marginal setae; cerci setulose, elongate and narrow, 2x as long as wide.