Hilara quasigriseola Jonassen, 2021

Jonassen, Terje, Andersen, Trond, Salmela, Jukka, Suuronen, Anna & Vaesoja, Matti, 2021, Six new species of Empididae and Hybotidae (Diptera, Empidoidea) from Fennoscandia, Norwegian Journal of Entomology 68, pp. 174-186 : 177-178

Hilara quasigriseola Jonassen sp. n.

( Figure 2A–B )

Type material. Holotype ♂, NORWAY: Finnmark, Kautokeino, Lahpoluoppal, Nahpoljohka N69.21029° E23.76200°, 320m. a.s.l., 09–24 July 2010, Malaise trap no. 4, Finnmarksprosjektet ( ZMBN) . Paratypes: 1♂ same data as holotype ; 3♂♂, Finnmark, Sør-Varanger, Sametijohka at Sameti , N69.40106° E29.71923°, 43m .a.s.l., 19–24 June 2010, Malaise trap no. 8, Finnmarksprosjektet ( ZMBN) .

DIffEREntIAL dIAgnOsIs. Very similar to Hilara griseola Zetterstedt, 1838 , but differs as fore tibia and fore metatarsus are more slender. Apical bristle on fore tibia is longer, and humeral bristle shorter than in H. griseola . Mid tibia with row of 2–4 ventral bristles which is lacking in H. griseola ; dorsally with a mixture of semi-erect and adpressed hairs, in H. griseola these are more uniformly adpressed. Squamal fringe dark, while pale in H. griseola . Hypandrium more produced posteriorly than in H. griseola , leaving the base of the apical narrow part of hypandrium free, not concealed by the epandrial lamellae as in H. griseola and H. morata Collin, 1927 (see Chvála 2005: fig. 131). Epandrial lamellae with apical process broad, short and blunt, not narrow and digitiform as in H. griseola .

Description. Male. Body length 3.4–3.6 mm, wing length 4.0– 4.5 mm.

Head. Frons and face broad, greyish dusted, occiput greyish dusted. Bristles and hairs on head all black. Single pair of ocellar bristles and single pair of frontal bristles equally long and strong. With 4–6 strong, upper postocular bristles present. Antenna black, style about as long as third segment, bare part of style very short. Palpus black, greyish pollinose, about as long as the combined length of first and second antennal segments. With strong, black bristle slightly in front of middle of palpus, all other preapical bristles not more than half its length. Proboscis black, subequal to height of head.

Thorax. Black, densely brownish-grey dusted, no distinct stripes. Acrostichals as long as bristle-like dorsocentrals, all black. Acrostichals widely biserial, divergent, dorsocentrals about 9–10 bristles in single row, distance between dorsocentrals and acrostichals slightly longer than between acrostichals rows. With 3 notopleural bristles, the anterior shortest, subequal in length to humeral bristle. Pronotum with single bristle on each side. With 4 scutellar bristles, apical pair longest.

Legs. Slender, moderately long, blackish with fine greyish pollinosity, fore and mid knees only slightly paler. All hairs and bristles black, more yellowish only beneath mid femur, at least towards coxa. Fore tibia ( Figure 2A ), with few distinct bristles, but with single, long, dorsal preapical bristle, about half the length of metatarsus. Mid femur with widely spaced row of anterodorsal bristles. Mid tibia with 2–4 ventral bristles, the longest stout, about as long as width of tibia. Hind tibia with about 4 dorsal bristles, at least one of these, plus apical bristle more than twice as long as width of tibia. Anteroventral bristles on hind tibia comparatively long, one of these at least as long as width of tibia. Fore tibia slender, only weakly widening distally. Fore metatarsus cylindrical, about half the length of fore tibia, nowhere wider than apex of fore tibia, all following tarsomeres clearly longer than wide. Mid tibia slender, cylindrical, dorsally with mixture of adpressed and semi-erect hairs, some of the latter becoming almost bristle-like posterodorsally. Hind tibia slender, only weakly widening distally.

Wing. Brownish with brown veins. Stigma indistinct, long, faintly brownish. Single long, black costal bristle present. Anal vein weak, becoming invisible towards wing margin. Halter yellow. Squama dirty yellow with fringe of darkened hairs.

Abdomen. Black, brownish dusted. All hairs and bristles black. Hairs sparsely distributed all over abdomen, hind-marginal bristles distinct.

Terminalia ( Figure 2B ) small. Hypandrium produced posteriorly, leaving base of apical narrow part of hypandrium free. Epandrial lamellae with apical process broad, short and blunt.

Female. Unknown.

Etymology. From Latin quasi, meaning like or similar, and griseola , diminutive of the Latin adjective griseus, meaning grey, referring to the similarity to Hilara griseola .

Distribution and biology. The species is taken in northern Norway, where it was collected close to moderately to fast flowing streams and rivers with banks grown with birch ( Betula ) and willow ( Salix ) ( Ekrem et al. 2012).

Figures

FIGURE 2. Details of Hilara quasigriseola Jonassen sp. n., male. A. Foreleg. B. Terminalia, lateral view.