Bibiodes

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 75-79

Bibiodes sp.

( Fig. 212)

This species is represented by a single female specimen.

Material. NMB F 2136 (1 female)

Localities. Kleinkembs

Diagnosis. The single female specimen is not well enough preserved to be reliably separated from B. provincialis , but the antenna appears to be more slender, and the section where veins Rs and M are fused appears to be shorter than in B. provincialis .

Description. Male unknown.

Female: Total length 6.5 mm (N=1).

Fig. 208 . Male, head and thorax. MNHN Aix 1079. Fig. 209 . Female, habitus. MNHN Aix 959.

Fig. 210 . Female, hind leg. MNHN Aix 23.

Fig. 211 . Male, terminalia. MNHN Aix 1079.

Fig. 214. Female, head and thorax. FSL 391913.

Head: Length 0.7 mm (N=1). Black. Compound eye relatively small. Ocellar tubercle tall and prominent. Antenna not well preserved but appears to be relatively slender.

Thorax: Length 2.2 mm (N=1). Black. Scutum strongly developed, relatively flat. Haltere dark reddish brown.

Wing: Length 6.0 mm, width 2.1 mm, length/width = 2.92 (N=1). Hyaline, veins yellowish, pterostigma oval, light brown, distinctive. Costa extends slightly beyond apex of R4+5. Subcosta fine and indistinctive, humeral vein probably present. Radial sector and M merged for a short distance. M and CuA with relatively short stems and long forks. Wing vein measurements in Table 5 .

Legs: Blackish-brown, presumably black in life, robust. Fore femur length 1.4 mm, width 0.62 mm, fore tibia length 1.5 mm, with short, stout spur, less than one third as long as spine. Hind femur length 1.9 mm, width 0.44 mm, stout throughout, hind tibia length 2.0 mm, width 0.27 mm, slender, first tarsomere slender.

Abdomen: Chestnut-brown, rather stout, cylindrical. Length 3.8 mm (N=1).

Terminalia: The tergites of the last three segments are apparently missing, so the internal structures are uncovered. Genital fork and two spermathecae are clearly visible, but a third spermatheca may be partly hidden.

Material examined. Holotype (female) of Bibio luteipennis FSL 391913 (A 16). Paratype (female) of Bibio luteipennis FSL 391914 (A 86).

Localities. Aix-en-Provence.

Diagnosis. A medium-sized Dilophus , 5.5 – 6.0 mm. Mesonotum black, pleurae yellowish, legs yellowishbrown with black tarsi. Protibia possibly with three mesal spines. Wing hyaline with small, dark brown pterostigma.

Redescription. Male unknown. There are several male Dilophus specimens from Aix-en-Provence in MNHN, but it is highly uncertain if these belong to D. luteipennis .

Female: Total length 5.5 – 6.0 mm (N=2).

Head (fig. 214): Length 0.7 mm (N=1). Black. Antenna short and stocky, segments not possible to count in the specimens at hand.

Thorax: Length 1.3 – 1.5 mm (N=2), width 1.4 mm (N=1). Mesonotum black, pleura brownish-yellow. Spine rows not possible to see in the specimens at hand.

Wing (fig. 213): Length 4.0 – 4.6 mm (N=2), width 1.5 – 1.8 mm (N=2). Hyaline, pterostigma small, oval and dark brown, R-veins dark brown, posterior veins colourless. Costa extends to apex of R4+5.Crossvein R-M slightly longer then basal part of R s. Wing vein measurements in Table 5 .

Legs: Yellowish-brown, tarsi black. Protibia rather stout, possibly with three mesal spines. Hind femur 1.3 mm, hind tibia 1.2 mm (N=1).

Abdomen: Length 3.7 – 4.4 mm (N=2), width 1.5 mm (N=1). Cylindrical, dark brown.

Terminalia: Cerci rather long, apically blunt, slightly hooked.

Figures

FIGURES 207 – 211. Bibiodes provincialis sp. n. Fig. 207. Female, wing. MNHN Aix 23.

Tables

TABLE 5. Bibiodes and Dilophus spp., wing measurements

Measurement	B. provincialis m	B. provincialis f	D. luteipennis f
Total length	4.3-5.8 (3)	5.2-6.5 (3)	3.8-4.5 (2)
Total width	1.7-2.5 (2)	2.0-2.7 (3)	1.5-1.7 (2)
MA-First branch of R	1.4 (1)	1.4-1.7 (2)	0.9-1.2 (2)
R 1	1.1 (1)	1.5-2.0 (2)	1.0-1.6 (2)
R s	0.8 (1)	0.7-0.8 (2)	0.4-0.6 (2)
R s +M	0.23 (1)	0.4-0.7 (2)	N.A.
R 4+5	-	2.2-3.1 (2)	2.0-2.7 (2)
M basal to R-M	1.5 (1)	0.9-1.4 (2)	0.9 (1)
M distal to R-M	-	0.5-0.7 (2)	0.6-1.1 (2)
M 1	-	1.9-2.2 (2)	1.5-1.7 (2)
M 2	-	1.7-2.1 (2)	1.3-1.5 (2)
R-M	N.A.	N.A.	0.22-0.36 (2)
M-Cu	-	0.30-0.49 (2)	-
CuA	-	1.0-1.3 (2)	-
CuA 1	-	2.4-3.4 (2)	-
CuA 2	-	1.9-2.2 (2)	-
Genus Dilophus Meigen, 1803
Dilophus luteipennis (Theobald, (Fig. 71, 213 – 214)	1937) comb.n.
Bibio luteipennis Théobald, 1937: 333 .