Identification key to the species of Apterodela

1(2) Wingless (Fig. 143). Pronotum indistinctly longitudinal or sub-quadrate (Figs 103–135, 138–140), PW / PL = 0.81–1.09. Elytra with or without subapical sinuate notch, shoulders narrow and sloping (Figs 153–179, 183–189, 193–212), EW/EHW = 1.41– 1.86. Internal sac with cylindrical and sharp medial tooth (Figs Figs 237–241, 251–255, 258–262, 265, 267, 271)....................................................................................... Apterodela Rivalier, 1950 (5)

2(1) Winged (Figs 144, 145). Pronotum clearly transverse (Figs 136, 137, 141, 142), PW / PL = 1.1–1.22. Elytra always without subapical sinuate notch, shoulders wide and rectangular (Figs 180–182, 190–192), EW/EHW = 1.2–1.4. Internal sac with flatt and blunt medial tooth (Figs 242, 243, 256, 257, 263, 264).......................... Protoapterodela subgen. nov. (3)

3(4) Labrum indistinctly tridentate (Figs 96, 101). Metathorax and metepisternum dense and evenly pubescent (Fig. 151). Middle band complete, slightly sinuate, with short lateral portion; supra-apical dot large, oval, or comma-shaped; sub-humeral dot absent (Figs 180, 181, 190, 191). BLL and BLR virtually undeveloped (Figs 242, 249, 256, 263). China: Taiwan ..................................................................................... A. (P.) shirakii (W. Horn, 1927)

4(3) Labrum clearly tridentate (Figs 97, 102). Metathorax and metepisternum glabrous (Fig. 152). Middle band incomplete, presented by small basal portion; sub-humeral dot small; apical dot absent, sometimes white elytral pattern completely undeveloped (Figs 182, 192). BLL and BLR vell developed (Figs 243, 250, 257, 264). USA ............. A. (P.) unipunctata (Fabricius, 1775)

5(6) Metepisternum sparsely pubescent (Fig. 146). Labrum in males tridentate (Figs 83, 84). Supra-apical dot large, comma-shaped; sub-humeral dot absent; elytra of females with black sub-sutural dot in basal third (Figs 153, 154, 163, 164). Japan ................................................................................... A. (A.) ovipennis (Bates, 1883)

6(5) Metepisternum glabrous (Figs 147–150). Labrum in males unidentate (Figs 63–67, 73–77, 85–87, 93–95, 99). Supra-apical dot often absent, rarely small; sub-humeral dot small or virtually invisible; elytra of females without black sub-sutural dot in basal third. China ......................................................................................... 7

7(8) Elytra with deep sinuate subapical notch, especially in males (Figs 193–212).................................... 11

8(7) Elytra with shallow or virtually undeveloped subapical notch (Figs 155–162, 165–179, 183–189)........................................................................................... A. (A.) bivirgulata (Fairmaire, 1889) (9)

9(10) Apical portion of middle band larger, predominantly rounded (Figs 155–162, 165–172); body less convex (Fig, 277)............................................................................ A. (A.) b. bivirgulata (Fairmaire, 1889)

10(9) Apical portion of middle band smaller, often elongato-transverse (Figs 173–179, 183–189); body more convex (Fig, 277).............................................................................. A. (A.) b. occidentalis ssp. nov.

11(12) Scape with 1–4 short setae except apical one (Figs 57, 58). White elytral pattern consists of relatively long thin and distinctly sinuate centro-apical portion of middle band (Fig. 202, 212). Aedeagus with relatively long and broad apex ended by small, rounded knob (Figs 224, 234); internal sac with large, sharply curved mt and large BLR (Figs 241, 255, 262).......................................................................................... A. (A.) alopecomma sp. nov.

12(11) Scape except apical seta glabrous (Figs 51–56). White elytral pattern consists of short drop-shaped apical portion of middle band (Figs 193–201, 203–211). Aedeagus with elongate, cylindrical, or slightly broadened apex ended by large, rounded knob (Figs 220–222, 232, 233) or without it (Fig. 223); internal sac with straight mt and small BLR Figs 239, 240, 253, 254, 260, 261).............................................................................................. 13

13(14) Elytra with weakly rounded lateral margins (Figs 193–198, 201), longer and narrower, EW/EHW = 1.46–1.76. Aedeagus shorter, EL/AL = 1.9–2.26, apex with rounded knob (Figs 220–222)........................................... 15

14(13) Elytra with clearly rounded lateral margins (Figs 199, 200), shorter and wider, EW/EHW = 1.71–1.78. Aedeagus longer, EL/AL = 1.88–2.04, apex without knob (Fig. 223)............................................... A. (A.) latissima sp.nov.

15(16) Labrum longer, LW/LL = 1.2–2.0 (Figs 93, 98). Pronotum with straight sides evenly converged to base (Figs 133, 138). Elytra flatter, TL/BH = 3.53–4.59, with deep subapical notch (Figs 201, 211). Aedeagus shorter, EL/AL = 2.14–2.26, with short straight apex and long lateral flanks (Figs 222, 233)............................... A. (A.) kazantsevi (Matalin, 2001)

16(15) Labrum shorter, LW/LL = 1.5–2.4 (Figs 85–87, 90–92). Pronotum with virtually subparallel lateral margins distinctly converging before hind angles (Figs 124–127, 129–132). Elytra more convex, TL/BH = 3.62–4.78, with shallower subapical notch (Figs 193–198, 203–210). Aedeagus longer, EL/AL = 1.9–2.17, with longer apex and short lateral flanks (Figs 220, 221, 232)............................................................................... A. (A.) lobipennis (Bates, 1888)