1 Prosternum clothed entirely with white to brownish silky, hair-like setae ( Fig. 3D); sternite 6 with cluster of strong golden setae; sternite 7 with pair of horn-like projections ventrally ( Fig. 3C).................... R. ( Ctenempis) albopilosa Coquillett
- Prosternum bare; sternite 6 without row of golden setae; sternite 7 unmodified or modified different than above.......... 2
2 Cerci directed anteriorly ( Figs 6A, 9C, 12B, 15B) (subgenus Dasyrhamphomyia)................................... 3
- Cerci directed posteriorly............................................................................... 6
3 Thorax short haired (setae shorter than gaps between rows) with acrostichals and dorsocentrals 1–2 serial, with brown vittae beneath rows; cerci with dark apex, with left cercus overlapping right at tip ( Figs 12B, C); hind tibia with anteroventral row of dark, stout, spine-like setae shorter than half tibial width.................................. R. ( D.) leptidiformis Frey
- Thorax long haired (setae longer than gaps between rows) with acrostichals and dorsocentrals 2–4 serial, without brown vittae beneath rows; cerci not darkened at apex, with right cercus overlapping left at tip ( Figs 9D, 15C); hind tibia without anteroventral row of dark, stout, spine-like setae..................................................................... 4
4 Cerci pale, elongate, extending to tergite 3, overlapping subapically in addition to apical overlap ( Figs 15B, C)........................................................................................... R. ( D.) nigrita Zetterstedt
- Cerci brownish to black, shorter, extending to tergite 5, only overlapping apically ( Figs 6A, 9C)....................... 5
5 Dichoptic; abdomen with setae longer than length of abdominal tergites; cerci blackish ( Fig. 6A); hind tibia and femur with pronounced fine, pale ventral pubescence ( Fig. 6C).................................... R. ( D.) erinacioides Malloch
- Holoptic; abdomen with setae shorter than length of abdominal tergites; cerci pale brown ( Fig. 9C); hind tibia and femur with long setae beneath ( Fig. 9A)...................................................... R. ( D.) hovgaardii Holmgren
6 Wing without dm-m crossvein (cell dm open) ( Fig. 62C); scutum with shiny vittae................................................................................................. R. ( Pararhamphomyia) diversipennis Becker
- Wing with dm-m crossvein (cell dm closed), sometimes dm-m crossvein or M 2 base absent in R. ( P.) omissinervis Becker; scutum without shiny vittae............................................................................. 7
7 Cercus with distinctive finger-like projection dorsally near base ( Figs 53B, 60A)................................... 8
- Upper margins of cercus without finger-like projections....................................................... 9
8 Large species (wing length more than 5 mm); phallus curvature occurring before folding into epandrium; cercal finger-like projection stout ( Fig. 53B); mid tibia with at least 3 preapical anteroventral and posteroventral setae dark, stout, spine-like..................................................................................... R. hirtula Zetterstedt
- Small species (wing length less than 4 mm); phallus curvature hidden within epandrium; cercal finger-like projection slim, short, less than half cercal length ( Fig. 60A); mid tibia with 2 anterodorsals and 2 posterodorsals longer than twice tibial width................................................................................ R. setosa Coquillett
9 Tergite 8 long, subequal to length of epandrium ( Iceland only) ( Fig. 46B).................... R. ( P.) simplex Zetterstedt
- Tergite 8 shorter than length of epandrium................................................................ 10
10 Subepandrial sclerite prolonged into pair of medioposterior lobes beneath cerci ( Figs 31C, 28A, 25C, 34A, 36C, 38C, 40A).. .................................................................................................. 11
- Cercus without pair of subepandrial lobes beneath.......................................................... 17
11 Apex of subepandrial lobe forked....................................................................... 12
- Apex of subepandrial lobe unforked..................................................................... 14
12 Phallus stout, looping dorsally above cercus and epandrium; apex of phallus expanded with ridge of teeth-like projections ( Figs 28A, B).............................................................................. R. ( P.) helleni Frey
- Phallus slender, filamentous apically, extending slightly beyond epandrium; tip of phallus slender, tapered, lacking teeth-like projections......................................................................................... 13
13 Fore tarsomere 1 swollen, slightly broader than width of fore tibia at apex ( Fig. 31A); tergite 5 without stout posterolateral setae; subepandrial lobe with outer finger-like process lacking apical seta, longer than inner lobe ( Figs 31 C-E)............................................................................................ R. ( P.) hilariformis Frey
- Fore tarsomere 1 slender, narrower than width of fore tibia at apex; tergite 5 with several closely set stout posterolateral setae ( Fig. 38B); subepandrial lobe with slender, outer finger-like process bearing 1 very long, fine, black seta ( Figs 38C, D).................................................... R. ( P.) lymaniana Sinclair, Vajda, Saigusa & Shamshev sp. nov.
14 Phallus not forming loops.............................................................................. 15
- Phallus forming loops................................................................................. 16
15 Hind tibia with some anterodorsal, posterodorsal and dorsal setae more than 2X tibial width ( Fig. 25B); apex of subepandrial lobe rounded ( Figs 25A, C)............................ R. ( P.) frigida Sinclair, Vajda, Saigusa & Shamshev sp. nov.
- Hind tibia with anterodorsal, posterodorsal and dorsal setae shorter than 2X tibial width ( Fig. 34B); apex of subepandrial lobe pointed ( Fig. 34A)....................................................................... R. ( P.) hoeli Frey
16 Hind tibia clavate ( Fig. 36D); hind tarsomere 1 shorter than length of tarsomeres 2–4 combined ( Fig. 36D)............................................................................................ R. ( P.) kjellmanii Holmgren
- Hind tibia not clavate ( Fig. 40B); hind tarsomere 1 longer than length of tarsomeres 2–4 combined ( Fig. 40B)........................................................................................... R. ( P.) omissinervis Becker
17 Phallus hidden within epandrium, leaving only base visible ( Fig. 17B)................................................................................. R. ( Eorhamphomyia) shewelli Sinclair, Vajda, Saigusa & Shamshev sp. nov.
- Phallus slim to hair-like, usually extending farther than length of epandrium, and often with curvatures................ 18
18 Phallus with distinct loop on apical half around apex of epandrium ( Figs 51C, 57A)............................... 19
- Phallus without loop, gradually curved................................................................... 20
19 Sternite 8 with stout, “horn-like” lateral projections ( Fig. 51D); phallus with loop forming acute angle ( Fig. 51C); hind tarsomere 1 swollen, wider than hind tibial width at apex ( Fig. 51B)................................ R. herschelli Malloch
- Sternite 8 without projections; phallus with small in-ward U-shaped loop ( Fig. 57A); hind tarsomere 1 slender ( Fig. 56B)........................................................................................ R. laevigata Loew
20 Midleg distinctly modified: femur strongly curved upwards; tibia curved inwards, with 3–5 dark, stout mid-posterodorsal setae longer than 2X tibial width; tarsomere 1 spindle-shaped, covered with dense, erect and moderately long setae ( Figs 42A, B)................................................ R. ( P.) petervajdai Sinclair, Vajda, Saigusa & Shamshev sp. nov.
- Midleg simple....................................................................................... 21
21 Apex of epandrium truncate ( Figs 44A, C); hind tibia with distinctive inward bend on apical part; hind tarsomere 1 spindleshaped, convex dorsally but straight ventrally ( Fig. 44B)................................................................................................... R. ( P.) septentrionalis Sinclair, Vajda, Saigusa & Shamshev sp. nov.
- Apex of epandrium rounded; hind tibia straight; hind tarsomere 1 clavate or uniformly slender....................... 22
22 Anepisternum shiny and scutum with 1–2 pairs of shiny vittae; hind tarsomere 1 clavate, increasing in size apically such that apical width broader than hind tibia ( Fig. 48B); cerci weakly constricted in middle, posterior half parallel to epandrium ( Fig. 48A).......................................................................... R. ( P.) ursinella Melander
- Anepisternum pruinose and scutum with pruinescent vittae; hind tarsomere 1 evenly slender, nearly as broad as apical width of hind tibia, ( Fig. 25B); cerci strongly constricted in middle, posterior half strongly divergent from epandrium ( Fig. 25A)....................................................................... R. ( P.) filicauda Henriksen & Lundbeck