Nanna Strobl, 1894

Ozerov, A. L. & Krivosheina, M. G., 2015, A review of the genera Cleigastra Macquart, Gonarcticus Becker, Gonatherus Rondani, Hexamitocera Becker, Nanna Strobl, Orthacheta Becker and Spathephilus Becker (Diptera, Scathophagidae) of Russia, Zootaxa 4012 (2), pp. 201-258 : 219

Nanna Strobl, 1894

Nanna Strobl, 1894: 77 [as subgenus of Cordilura Fallén, 1810 ]. Gender: feminine. Type species: Cordylura flavipes Fallén, 1819 , by designation of Vockeroth (1965: 830).

Amaurosoma Becker, 1894: 109 . Gender: neuter. Type species: Cordylura flavipes Fallén, 1819 , by original designation. Pselaphephila Becker, 1894: 122 . Gender: feminine. Type species: Pselaphephila loewi Becker, 1894 , by monotypy.

Nanna species are slender, small to medium-sized flies (about 3–6 mm long). Head. Frons and face yellow to black, parafacial and gena pale yellow. Postcranium black, greyish dusted, covered with yellow or black hairs and with black postocular setulae. Chaetotaxy: 2–3 orbital, 2–4 frontal, 1 ocellar, 1 inner vertical, 1 outer vertical (short), 1 postocellar; 1 pair of strong vibrissae and 1–2 pairs of short subvibrissae present. Scapus and pedicel yellow to black. Postpedicel black, with acutely angled upper apical corner ( Fig. 5 ), usually in male wider than in female, 2–5 times as long as wide. Arista black, bare or pubescent throughout its length. Palpus long, yellow.

Thorax black, greyish dusted or with shining spots. Scutum with following setae: acrostichals short in two rows, prescutellar pair not differentiated or only slightly longer than other acrostichals, dorsocentrals 3+3, intraalars 1+(1–2), supra-alars 1+2, postpronotals 2, notopleurals 2, postalars 2. Proepisternum with hairs in central part or bare, with 2 setae near lower margin. Proepimeron with 1 seta. Anepisternum covered with hairs in posterior half (usually pale yellow in male and black in female) and with 2–4 black setae along posterior margin. Katepisternum covered with long setae in ventral corner (the setae pale yellow in male and black in female) and 2–3 strong setae (if two, then anterior katepisternal seta absent). Anepimeron bare. Scutellum black, with pair of strong lateral scutellar setae and pair of apical setulae ( Fig. 7 ).

Legs yellow to black, but fore and mid tibiae usually yellow. Fore femur usually with rows of dorsal (anterodorsal) and posterodorsal setae, often with anteroventral, anterior or posteroventral setae. Fore tibia with 1– 2 dorsal (posterodorsal), 1–2 anterodorsal and 0–1 posterior setae at middle, and usually with apical ventral, dorsal and posterior setae. Mid femur with row of anterior, 1–2 anteroventral, 1 preapical posterior, and 0–1 preapical anterior setae. Mid tibia with 1 posterodorsal, 1 anterodorsal at middle, 0–1 anterior (anteroventral) setae, and ring of apicals. Hind femur usually with row of anterior, 0–2 preapical anterodorsal and 1–6 ventral setae. Hind tibia with 2 anterodorsal, 2 posterodorsal, 0–1 anteroventral, 1 preapical dorsal setae, and ring of apicals.

Wing clear or tinged with brownish; veins blackish; vein R1 bare. Calypters, margins of calypters, and halteres yellowish.

Abdomen cylindrical, black, subshining or greyish dusted, covered with hairs. Tergites 2–6 each with row of marginal setae. Male sternite 4 simple, 1.5–2 times as long as wide. Male sternite 5 with triangular-shaped lobes (e.g. Fig. 78 ), often apically broadened, but it is evident laterally only ( Fig. 79 ) because the lobes usually are curved like propeller. Surstyli simple, cerci fused. Ovipositor moderately long, cylindrical ( Figs 163–165 ). Female tergite 7 desclerotized in middle, in some species forming syntergosternite (e.g. N. flavipes , Fig. 103 ). Female tergite 8 of V-like form, sternite 8 as one undivided or two small round sclerites.

Adults common in spring (in cold regions later) on grasses. Larvae develop in the flower heads of Phleum and Secale (Gramineae) (e.g. Ferrar, 1987).

Figures

FIGURES 1 – 8. Nanna flavipes (Fallén) (1, 2, 5, 7), Hexamitocera loxocerata (Fallén) (3), Spathephilus nigriventris (Loew) (4, 6) and Orthacheta cornuta (Loew) (8): 1 — thorax, lateral view; 2 — proepisternum; 3 — head, lateral view; 4, 5 — antenna, lateral view; 6 – 8 — scutellum. Figures 4 – 7 after Ozerov (2010 e, Figures 10 – 13).

FIGURES 74 – 81. Nanna articulata (Becker): 74 — fore femur, anterior view; 75 — male sternite 4; 76 — epandrium, cerci and surstyli, lateral view; 77 — same, dorsal view; 78 — male sternite 5; 79 — same, lateral view; 80 — female abdominal sternites 7 and 8; 81 — distribution map.

FIGURES 163 – 170. Nanna tibiella (Zetterstedt) (163 – 165) and Orthacheta cornuta (Loew) (166 – 170): 163 — end of female abdomen, ventral view; 164 — same, dorsal view; 165 — same, lateral view; 166 — male sternite 5; 167 — epandrium, cerci and surstyli, lateral view; 168 — same, dorsal view; 169 — male sternite 4; 170 — distribution map.

FIGURES 103 – 110. Nanna flavipes (Fallén): 103 – 105 — female abdominal sternite 8; 106 — male sternite 5; 107 — epandrium, cerci and surstyli, lateral view; 108 — same, dorsal view; 109 — male sternite 4; 110 — distribution map.