Plecia larguensis Gentilini, 1993

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 46-48

Plecia larguensis Gentilini, 1993

( Figs. 34 – 35, 129 – 131 )

Plecia larguensis Gentilini, 1993: 162

Material (tentative) (RGL) Bois d’Asson 5, Bois d’Asson 7, Dauphin 30, Bois d’Asson 47, Dauphin 182. Localities. Bois d’Asson

Diagnosis. A rather small species (6 – 7.5 mm). The species can be recognized on the hooked, pointed gonostyli and the epandrium bearing three long projections, further on the very short, nearly vertical vein R2+3 and the large, light brown pterostigma. The female is unknown, most likely rather similar to Plecia livida .

Redescription. Male: Total length 6.0 – 7.5 mm (N=5).

Head (fig. 130): Length 0.86 – 1.02 mm (N=3), width 0.84 – 1.02 mm (N=3). Antennal flagellum cylindrical, 9- or 10-segmented. Ocellar tubercle rather tall, rounded. Palp robust. Rostrum a little elongated, about two thirds as long as compound eye.

Thorax: Length 1.6 – 1.9 mm (N=5). Dark reddish brown.

Wing (fig. 129): Length 4.9 – 5.4 mm (N=5), width 1.9 – 2.1 mm (N=5), length/width = 2.42 – 2.65 (N=5). Light brownish fumose, pterostigma large, oval and light brown. Veins brown throughout, R-veins scarcely darker than posterior veins. Costa extends almost half-way between apices of R4+5 and M1. Subcosta fine and indistinctive. R2+3 short, nearly vertical, R4+5 nearly straight. Wing vein measurements in Table 2.

Fig. 130 . Male, head and thorax. RGL Bois d’Asson 7. Fig. 131 . Male, terminalia, dorsal. RGL Dauphín 182.

Legs: Reddish brown, femorae paler in basal half. Slender throughout. Fore femur 1.6 – 2.2 mm (N=4), fore tibia 1.9 – 2.1 mm (N=2), hind femur 2.2 mm (N=2), hind tibia 2.2 – 2.3 mm (N=2), hind first tarsomere 0.8 mm (N=1).

Abdomen: Length 3.9 – 4.9 mm (N=5). Brown, slender.

Terminalia (fig. 131): Hypopygium width 0.70 – 0.95 mm (N=4). Epandrium small, with three long, digitiform projections. Gonostylus 0.37 – 0.49 mm long (N=4), apically curved and sharply pointed.

Female unknown. The material from Bois d’Asson contains numerous females which are seemingly rather homogenous morphologically. This material presumably contains females of all the four nominal species named by Gentilini (1993), as well as Plecia livida .

Figures

FIGURES 129 – 131. Plecia larguensis Gentilini, 1993 Fig. 129. Male, wing. RGL Bois d’Asson 7.