Megaselia balfourbrownei sp. n.

(Figs 11–20)

Material examined. Holotype male, DENMARK, DK EJ, Nørre Onsild Mose (= bog), 21.v.–5.vi.2017, Esben Bøggild (CUMZ-8-158). 2 paratype males as holotype.

Description. Male. Head as Fig. 11. Cheek with 3 bristles and jowl with 2 that are longer and more robust. Postpedicels without SPS vesicles. Thorax brown. Two notopleural bristles and no cleft in front of these. Mesopleuron bare. Scutellum with an anterior pair of short hairs and a posterior pair of bristles. Abdominal tergites brown with numerous hairs that are longest at their rear margins, especially on T6. Venter gray and with hairs on segments 3–6. Hypopygium as Figs 12–15. Legs yellow to a little dusky. Fore tarsus (Fig. 16) with posterodorsal hair palisade on segments 1–4. Dorsal hair palisade of mid tibia extends about 0.73 times its length. Hairs below basal half of hind femur longer than those of anteroventral row of outer half (Fig. 17). Hind tibia (Fig. 18) with about a dozen differentiated posterodorsal hairs before the deflection of the dorsal hair palisade onto the anterior face, without anterodorsals, and spinules of apical combs simple. Wings (Figs 19 & 20) 1.60–1.85 mm long. Costal index 0.43–0.45. Costal ratios 3.5–3.7: 1.4–1.5: 1; or 1.7: 1, with vein 3 being unforked. Costal cilia (of section 3) 0.112–0.145 mm long. Hair at base of vein 3 0.02–0.03 mm long. With 3–4 axillary bristles, the outermost being 0.11–0.14 mm long. Sc not reaching R1. Haltere knob pale, almost white.

Recognition. Of the available specimens all but one have a forked vein 3. In the keys of Lundbeck (1922) the latter runs to Group vii, couplet 34 lead 1 to M. fuscohalterata (Schmitz) [a synomym of M. sulphuripes (Meigen)], but it has a different hypopygium and dark halteres. The costal index ranges from 0.42 to 0.45. Those with the CI 0.44 or more run to Group VI couplet 37 lead 2 to M. subtumida (Wood), which has a different hypopygium and vein Sc running to vein 1. Specimens with the CI <0.44 run to Group VII couplet lead 1 (see above). In the key to British species (Disney, 1989) it runs to couplet 20, but its hypopygium differs from the two species of this couplet and that of M. latericia Schmitz that runs to the same couplet. It has a different hypopygium (Figs 6 & 7 in Disney, 2011a).

Etymology. Named after the Balfour-Browne Fund that has provided small grants to RHLD over several years.