Plecia grossa ( Heyden & Heyden, 1865 )

Skartveit, John & Wedmann, Sonja, 2021, A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany, Zootaxa 4909 (1), pp. 1-77 : 26

Plecia grossa ( Heyden & Heyden, 1865) (figs. 32, 120–121)

Protomyia grossa Heyden & Heyden, 1865: 22 .

Localities: Rott.

Material examined: Holotype (female) NHMUK In 58791 (figs. 32, 120). The holotype is a rather faint impression.

Additional material (all females): LACMIP 2533.272/LACMIP Type 3404 (figured specimen), LACMIP 2533.1165, 2533.1198, 2533.1211, 2533.1220, 2533.1225, 2533.1226, 2533.1228, 2533.1229, 2533.1274, 2533.1290, 2533.1295, 2533.1305, 2533.1310, 2533.1318, 2533.1325, 2533.2239. Isolated wings: LACMIP 2533.1085, 2533.1162, 2533.1179, 2533.1180, 2533.1181, 2533.1187, 2533.1302.

Description:

Female (N= 25, figs. 32, 120–121):

Total length 6.6–8.5 mm (N=13)

Head: Length 0.77–1.01 mm (N=11), width 0.77–1.03 mm (N=9). Brown. Ocellar tubercle rather large. Complex eye oval, medium-sized. Flagellum 0.47–0.68 mm long (N=10), 0.10–0.14 mm wide (N=9) conical, relatively slender, segments not possible to count in holotype, 8–9-segmented in additional specimens. Palpus with last segment cylindrical.

Thorax: Length 1.9–2.6 mm (N=15), width 1.7–2.0 mm (N=8=), brown, haltere brownish-yellow.

Legs: Light brown, slender. Fore femur 1.5–2.1 mm long (N=4), 0.40 mm wide (N=1), fore tibia 1.6–2.3 mm long (N=7), 0.23–0.24 mm wide (N=4), first fore tarsomere 0.81–1.01 mm long (N=4), hind femur 2.0 mm long (N=1), hind tibia 2.2–2.6 mm long (N=3).

Wing (fig. 121): Length 6.0– 7.8 mm (N=23), width 2.6–3.1 mm (N=22), length/width = 2.27–2.71 (N=22), brownish fumose, costal cell somewhat darker, veins brown, fine. Humeral vein present, oblique. Pterostigma very indistinctive. Subcosta distinctive, straight, running well separated from R. Costa extends well beyond apex of R 4+5, almost half-way to apex of M 1. R 2+3 short to medium-length, basally nearly vertical, bent in middle. R 4+5 gently curved. Fork of M asymmetrical, M 1 strongly curved, M 2 nearly straight. CuA-veins apically straight. CuP basally strong, fading towards but reaching wing margin. Vein measurements are given in Table 4.

Abdomen: Length 4.0– 6.1 mm (N=15), width 1.8–2.5 mm (N=14), dark brown, robust. Cerci fine and small.

Male unknown.