Key to the European species of Diglyphus

1. Scape predominantly to completely pale (e.g. Figs 49–51, 67–70)...............................................2

- Scape predominantly to completely dark (e.g. Figs 52–64).....................................................7

2(1). Fore femur pale (Figs 1–6, 31, 32, 42).....................................................................3

- Fore femur with at least base dark brown and ±metallic (Figs 40, 41).............................................6

3(2). Mesoscutum green, scutellum and axillae purple (Figs 15, 16); hind femur variable, usually dark and metallic in basal ¾– ¼ (e.g. Fig. 42), sometimes totally pale; male: marginal vein not thickened, gaster with a pale spot subbasally (Fig. 16)................................................................................ D. pusztensis (Erdös & Novicky)

- Mesoscutum and scutellum with same colour: green, golden-green, bluish, or purple (Figs 1–6); male: gaster and marginal vein variable.............................................................................................4

4(3). Mesoscutum and scutellum metallic purple or golden-green with purplish reflections (Figs 5, 6); hind femur pale (Figs 5, 6) (very occasionally small males can have basal ½ of hind femur brown); male: marginal vein strongly enlarged, at least 1.2× as wide as width of costal cell at level of base of marginal vein (Fig. 77); male gaster with a pale spot subbasally (Fig. 6); on average a smaller species (0.9–1.4 mm)........................................................ D. clematidis sp. n.

- Mesoscutum and scutellum green, golden-green or bluish; hind femur dark and metallic in basal ½ (Figs 31, 32); male: gaster and marginal vein variable; on average larger species (1.2–2.1 mm).............................................. 5

5(4). Female antenna with first funicular 1.0–1.2× and second funicular 1.0× as long as wide (Figs 1, 49); male: gaster with a pale spot subbasally (Fig. 2), marginal and stigmal veins narrow, marginal vein 0.4× as wide as width of costal cell at level of base of marginal vein (Fig. 2)................................................................. D. albiscapus Erdös

- Female antenna with first funicular 1.6× and second funicular 1.3× as long as wide; male: gaster without a pale spot subbasally

(Fig. 4), marginal and stigmal veins enlarged, marginal vein 0.8× as wide as width of costal cell at level of base of marginal vein (Figs 4, 74)................................................................... D. anadolucus Doganlar 6(2). Hind tibia with basal ¾ dark (Figs 13, 14, 40)................................................ D. poppoea Walker

- Hind tibia dark at base only (Figs 17, 18, 41), occasionally completely pale......................... D. sabulosus Erdös

7(1). Fore wing speculum with dense setation (Fig. 73)............................................................ 8

- Fore wing speculum with sparse setation (e.g. Fig. 72)........................................................9

8(7). Mesoscutum green to blue, contrasting against purple scutellum (Figs 23, 24); setae on pronotum and mesoscutum dark........................................................................................ D. eleanorae Graham

- Mesoscutum and scutellum with about the same green or blue-green colour (Figs 9, 10) (very occasionally coppery), scutellum sometimes golden and mesoscutum green; setae on pronotum and mesoscutum pale.................... D. isaea (Walker)

9(7). Femora pale (Fig. 44).................................................................. D. subplanus (Erdös)

- Femora predominantly dark (e.g. Figs 33, 39, 40)........................................................... 10

10(9). Tibiae completely pale (Fig. 39)....................................................... D. pachyneurus Graham

- At least hind tibia with a dark ring at base (Fig. 33), usually with all tibiae at least partly dark (e.g. Figs 34, 40).......... 11

11(10). Hind tibia predominantly pale with a dark ring at base (Fig. 33), dark ring can be weak.............. D. begini (Ashmead)

- Hind tibia predominantly dark (e.g. Figs 34, 40)............................................................12

12(11). Scape with at least basal ¼ pale (Figs 65, 66)................................................ D. poppoea Walker

- Scape completely dark (e.g. Figs 54, 56, 61), or with very base pale............................................. 13

13(12). Males..............................................................................................14

- Females............................................................................................17

14(13). Fore wing with marginal vein thick, 0.9–1.1× as wide as width of costal cell at level of base of marginal vein (Figs 8, 75)........................................................................................ D. crassinervis Erdös

- Fore wing with marginal vein slender, 0.5× as wide as width of costal cell at level of base of marginal vein (e.g. Figs 12, 7 2)....................................................................................................15

15(14). Fore wing with stigmal vein short, 2.5× as long as wide (Fig. 30).............................. D. propodealis Szelényi

- Fore wing with stigmal vein long and slender (Fig. 29), 3.4–4.1× as long as wide..................................16

16(15). Flagellum stout, e.g. first flagellomere 1.5× as wide as width of pedicel, and flagellomeres densely clothed with short setae (Fig. 55); scutellum green (Fig. 22)....................................................... D. chabrias (Walker)

- Flagellum slender, e.g. first flagellomere 1.2× as wide as width of pedicel, and flagellomeres with longer setae that are more sparsely situated (Fig. 62); scutellum purple (Fig. 12)......................................... D. minoeus (Walker)

17(13). Mesoscutum long (Fig. 21), 0.72–0.86× as long as wide (mean = 0.80, n = 10)..................... D. chabrias (Walker)

- Mesoscutum short (Figs 7, 27), 0.63–0.70× as long as wide (mean = 0.66, n = 28).................................18

18(17). Scutellum purple (Fig. 11); main setae on mesonotum long and strong: posterior setae on midlobe of mesoscutum reach the transscutal articulation (Fig. 79a), anterior scutellar setae reach the base of posterior scutellar setae (Fig. 79c); mesopleuron and mesosternum violet-black to dark green; antenna with radicle and scape dark................... D. minoeus (Walker)

- Scutellum green to golden-green, sometimes with coppery reflections; main setae on mesonotum slender and short: posterior setae on midlobe of mesoscutum do not reach transscutal articulation (Fig. 79b), anterior scutellar setae reach slightly longer than half the distance between bases of anterior and posterior setae (Fig. 79d); mesopleuron and mesosternum shiny metallic green to blue-green (e.g. Figs 35, 43); antenna with scape and radicle variable....................................19

19(18). Stigmal vein more slender (as in Fig. 29), 3.5× as long as wide; antenna with radicle and basal ¼ of scape pale................................................................................................ D. crassinervis Erdös

- Stigmal vein more stout (Fig. 30), 2.5× as long as wide; antenna with radicle and scape dark........ D. propodealis Szelényi