Megaselia jonasseni Henry & Bøggild 2019, sp. n.

Megaselia jonasseni sp. n.

(Figs 63–71)

Material examined. Holotype male, DENMARK, Dk EJ, Nørre Onsild mose (= bog), 21.vi.–7.vii..2017, Esben Bøggild (CUMZ-8-183). Description. Male. Frons with very fine crowded micotrichia and as Fig. 63, most notably with the upper supra-antennal bristles further apart than the pre-ocellars. Cheek with 5 bristles and jowl with 2 that are very much longer and more robust. Postpedicels (Fig. 63) without SPS vesicles. Palps and proboscis as (Fig. 64). Thorax brown, with 2 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 fine hairs that are longest at rear of T6. Venter dark gray, and with hairs on segments 3–6. Hypopygium as Figs 65–67, the hairs on the epandrium being longer than those on T6. Legs brown to yellowish brown front legs. Fore tarsus (Fig. 68) with posterodorsal hair palisade on segments 1–4 and 5 longer than 4. Dorsal hair palisade of mid tibia as Fig. 69. Hind femur as Fig. 70. Hind tibia with 10 well differentiated posterodorsal hairs, without anterodorsals, and spinules of apical combs simple. Wings (Fig. 71) 2.17 mm long. Costal index 0.53. Costal ratios 3.53: 1.84: 1. Costal cilia (of section 3) 0.14 mm long. Hair at base of vein 3 0.10 mm long. With 3 axillary bristles, the outermost 0.18 mm long. Sc not reaching R1. Haltere brown.

Recognition. In the keys of Lundbeck (1922) it runs to Group VI couplet 26 lead 1, but its hypopygium is different. In the key to British species (Disney, 1989) it runs to couplet 285, lead 2, but its costal index exceeds 0.5 compared to being less than 0.46 in M. rivalis (Wood). In Borgmeier’s (1966) key to Nearctic Group VII it runs to couplets 35 or 41. At 35 the hypopygium differs and the yellow palps and longer dorsal hair palisade of the mid tibia exclude a subsequently added species. At couplet 41 the hypopygium differs and with its CI exceeding 0.5 excludes a subsequently added species along with its CI being less than 0.4.

Etymology. Named in honour of Terje Jonassen, the Norwegan dipterist.