Plecia lygaeoides ( Heer, 1849 )

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 51-53

Plecia lygaeoides ( Heer, 1849)

( Figs. 38 , 40, 42 – 44, 144 – 148)

Protomyia lygaeoides Heer, 1849: 232 – 233.

Bibio lignarius Germar, 1837 , sensu Unger, 1842, misidentification, pro parte. Protomyia gracilenta Heyden & Heyden, 1865: 28 . Syn.n. Bibio detractus Theobald, 1937: 336 Syn. n.

Plecia guinieri Théobald, 1937: 408 Syn. n.

Plecia acutiventris Théobald, 1937: 410 Syn. n.

Protomyia lygaeoides was described from Radoboj and later noted from Aix-en-Provence by Heer (1856). The type is in Landesmuseum Joanneum, Graz and an additional specimen from Aix-en-Provence is in ETHZ. Protomyia gracilenta was decribed from Rott, Plecia acutiventris and Bibio detractus from Aix-en-Provence.

Material examined. Female identified as Bibio lignarius sensu Unger SLJG 259. Female (NHMUK In 39822). Holotype (male) of Protomyia gracilenta NHMUK In 58805. Cotypes (2 males 1 female) of Plecia guinieri EEFN (coll. Fliche) F 190. Cotype (female) of Plecia guinieri EEFN (Coll. Fliche) F 239. Holotype (male) of Plecia acutiventris FSL 391937 (A84), EEFN F 169 (status of both specimens given as “holotype” in figure legends (Pl. XXII Fig. 9 and Pl. XXIX Fig. 14) by Théobald (1937)). Holotype (male) of Bibio detractus FSL 391921 (A 21). Paratype (male) FSL 391922 (A 29).

Other material: 9 males EEFN (Coll. Fliche) F 176, F 182, F 187, F 188, F 200, F 207, F 268, F 302, F 320. Female (FSL 391902), Chadrat.

Localities. Aix-en-Provence, Chadrat (Radoboj, Rott)

Diagnosis. A medium-sized, dark Plecia . The wings are blackish fumose with all veins black, Pterostigma oval and distinctive, vein R2+3 straight and oblique. Male gonostylus long and slender.

Redescription. Male: Total length 7.0 – 9.5 mm (N=14).

Head (fig. 145): Length 1.0 – 1.1 mm (N=34), width 1.1–1.3 mm (N=3). Flagellum 0.48 mm long, 8-segmented.

Thorax: Length 1.9 – 3.0 mm (N=7), width 1.8 – 2.1 mm (N=4). Entirely black.

Wing: Length 4.8 – 7.0 mm (N=14), width 2.0 – 2.5 mm (N=5), length/width = 2.45 – 3.00 (N=5). Dark brownish fumose, all veins pigmented, dark brown. Pterostigma oval, dark brown, moderately distinctive. Vein R2+3 straight and oblique. Wing vein measurements in Table 2.

Legs: Dark brown to black, slender, tibiae conspicuously thin. Fore tibia 2.0– 2.6 mm (N=4), hind femur 1.8 mm (N=1), hind tibia 2.1–2.9 mm (N=4).

Abdomen: Length 4.6–5.3 mm (N=5), width 1.1 – 1.6 mm (N=4), black, slightly conical.

Terminalia (fig. 147–148): Hypopygium width 0.79–0.80 mm (N=3), gonostylus length 0.39 – 0.53 mm (N=3). Gonostylus digitiform, rather narrow.

Female: Total length 8.0– 11.4 mm (N=6), entirely black.

Head (fig. 146): Length 0.81–1.05 mm (N=2), width 1.30–1.35 mm (N=2). Black. In dorsal view with prominent hind corners. Antenna relatively long and robust, flagellum 10-segmented. Flagellum length 0.74 mm (N=1). Palp strong.

Fig. 145. Male, head, NHMUK In 58805.

Fig. 146. Female, head. ETHZ.

Fig. 147. Male, terminalia, ventral. RGL Céreste 522. Fig. 148. Male, terminalia, dorsal. FSL 391921.

Thorax: Length 2.0 – 3.1 mm (N=6), width 2.0– 2.4 mm (N=4). Black, haltere brown.

Wing (fig. 144): Length 6.2 – 9.8 mm (N=7), width 2.5–3.6 mm (N=4), length/width = 2.43 – 2.55 (N=4). Blackish fumose with blackish veins. R2+3 oblique. Wing vein measurements in Table 2.

Legs: Black. Hind femur moderately clavate, otherwise slender. Length of fore femur 2.0 mm (N=1), fore tibia 1.7 – 2.9 mm (N=4), hind femur 2.8 mm (N=1), hind tibia 2.8–3.2 mm (N=2).

Abdomen: Length 5.7 – 8.7 mm (N=6), width 2.1 – 3.3 mm (N=3). Black.

Terminalia: Cerci small and rounded.

Figures

FIGURE 38. Plecia livida, male. Holotype of Plecia acutiventris Théobald, MNHN Ex. 169. FIGURE 39. Plecia livida, female. Holotype of Plecia goreti Théobald, MNHN B 24516. FIGURE 40. Plecia livida, female. Paratype of Plecia guineri Théobald, MNHN B 24415. FIGURE 41. Plecia livida, male. Holotype of Plecia maculiventris Théobald, MNHN B 24523. FIGURE 42. Plecia lygaeoides, female. Holotype of Protomyia lygaeoides Heer, SLJG 77465.