griseifrons Becker, 1910

Naglis, Stefan & Negrobov, Oleg P., 2017, West Palaearctic species of the Hercostomus species-group III (Diptera, Dolichopodidae), with description of a new species from Turkey, Alpine Entomology 1, pp. 33-38 : 34-35

griseifrons Becker, 1910

Hercostomus griseifrons Becker, 1910: 649

Type locality.

France (Corsica).

Distribution.

France, Germany, Italy, Ukraine.

Redescription of Hercostomus griseifrons based on type material

(Museum fur Naturkunde, Leibniz-Institute for Evolution and Biodiversity Science). Since Becker has not designated a holotype, a lectotype is designated on order to stabilize the nomenclature.

Lectotype: 1>, Corsika, 54652, V. Paralectotype: 13>, 9 +, same data, 54652, V und 55290 VI (pres design.).

Redescription.

Male. Body length 2.4 mm, wing length 2.3 mm. Head: frons metallic green, shiny, with slightly white pruinosity. Face silvery white. Postocular cilia in the lower part of the head dark. Proboscis brown, palpus dark brown. Antennae brown. Postpedicel big oval, pubescent with short white hairs, length more than the width. Arista dorsal, located closer to the base of the postpedicel, glabrous. The ratio of the length of the scape and pedicel to the length of the postpedicel: 2.1: 2.9: 2.4. Thorax: mesonotum metallic green, shiny. Pleura greenish-brown, with gray pruinosity. Scutellum from above bare, along the margin of the scutellum there are a few small hairs, with two strong marginal setae and one small lateral seta. ppls with 1 strong black seta and a group of light hairs. Legs: yellow, hind femur in apical part black. Fore tibia with 1 ad seta, without a series of anterior hairs. Fore tibia and tarsomeres relative podomere ratios: 5.3: 2.4: 1.0: 0.8: 0.5: 0.8. Mid and hind femora with one strong black preapical seta. Mid tibia with 2 ad, 2 pd setae. Mid tibia and tarsomeres relative podomere ratios: 7.3: 3.3: 1.6: 1.8: 0.8: 0.9. Hind tibia with 2 ad and 2 dorsal setae. Hind tibia and tarsomeres relative podomere ratios: 8,8: 1,9: 2,6: 1,7: 1,2: 1,0. Wing: The costal vein at the junction with R1 not thickened. The ratio of the length of the segment of the costal vein between R 2 + 3 and R 4 + 5 to the length of the segment of the same vein between R 4 + 5 and M 2.1: 0.7. Apical part of R 4 + 5 and M smoothly bent, converging in the apical part of the wing. Basal section of M slightly longer than distal section 8.5: 8.4. dm-cu straight, located in the middle of the wing. The ratio of the length of the basal segment of CuA to the length of the apical segment of the same vein: 6.4: 3.6. The apical segment of CuA is 1.5 longer than crossvein dm-cu. Anal wing of the wing is developed. The anal corner is blunt. Halter yellow. Lower calypter yellow, with black setae. Abdomen: The abdomen is metallic-green, shiny, with black setae and hairs. Hypopygium brown. Epandrium oval, its length is longer than the width, the apical part is almost straight. Cercus expanded in apical part, their length is more than twice the width.

Female: differs from the male by a broader face and a more intense darkening of the apex of the hind femora.