Megaselia birgittemarkae Henry & Bøggild 2019, sp. n.

Megaselia birgittemarkae sp. n.

(Figs 21–31)

Material examined. Holotype male, DENMARK, Døstrup Simested Å, 13.viii.–20.ix.2016, E. Bøggild (CUMZ- 8-62).

Description. Male. Head as Fig. 21. Cheek with 2 bristles and jowl with 2 that are longer and more robust. Postpedicels without SPS. Labella from below as Fig. 22. Thorax brown. With 3 notopleural bristles and no cleft in front of these. Mesopleuron bare. Scutellum with an anterior pair of small hairs and a posterior pair of bristles. Abdominal tergites brown with small hairs but longer at the rear of T6 (Fig. 23). Venter gray, and with small hairs on segments 3–6. Hypopygium as Figs 23–25. Legs yellowish but the hind femur gradually darkening towards its tip (Fig. 28). Fore tarsus with posterodorsal hair palisade on segments 1–4 and 5 longer than 4 (Fig. 26). Dorsal hair palisade of mid tibia extends almost two thirds its length (Fig. 27). Hairs below basal half of hind femur longer than those of anteroventral row of outer half (Fig. 28). Hind tibia with about 15 differentiated posterodorsal hairs, without anterodorsals (Fig. 28), and spinules of apical combs simple. Wings (Fig. 29) 1.42 mm long. Costal index 0.41. Costal ratios 5.2: 2.1–2.2: 1. Costal cilia (of section 3) 0.09 mm long. Hair at base of vein 3 0.03 mm long. With 2 unequal axillary bristles, the outermost being 0.10 mm long. Sc almost reaching or just reaching R1, depending on the focus (Figs 30 & 31). Haltere knob grayish.

Recognition. In the key of Lundbeck (1922) to Group VII it runs to couplet 6, lead 1 to M. lactipeniis (Lundbeck), which however has brown legs, or to couplet 19, lead 1 to M. lata (Wood), which has a different hypopygium. In the key to the males of the British Isles (Disney, 1989) two critical characters, the grayish colour of the haltere knob and whether vein Sc runs to vein 1 or not depending on the focus, are intermediate. It runs to couplet 191, but neither option fits. Alternatively it runs to couplet 204, where lead 1 runs to couplet 235 lead 2 to M. lutescens (Wood), but its hypopygium is clearly different. Two further species running to this couplet have the costal index exceeding 0.5, apart from different hypopygia. Treating the haltere knob as dark it runs to couplet 267, lead 2, which returns one to couplet 190 and on to 191, where the hypopygia clearly differ. Of species not covered by the key M. intergeriva Schmitz runs to couplet 267, but its hypopygium also clearly differs (see Disney, 2011a). M. garwolinensis Disney & Durska (2014) runs to couplet 191 but its labella are not enlarged and spinose and its hypopygium differs.

Etymology. Named after Birgitte Mark, a colleague of Esben Bøggild.