Key to West Palaearctic genera of Nematini

As supported by genetic data, the genera comprising the Dineurini form a monophylum distinct from the Nematini . However, Dineura and Nematinus of the Dineurini are morphologically very similar to some Nematini . For practical reasons, they are included in the key below. Specimens of Anoplonyx and Platycampus can also be confused with members of Nematini, but in their forewing the base of vein 2A+3A is complete and curved up to 1A (cell PA closed) (Prous et al. 2019). When in extremely rare cases specimens of Nematini have this wing character, or Anoplonyx and Platycampus lack it, consider additional characters. Anoplonyx females have a distinctly emarginate clypeus, simple claws, valvula 3 not tapering towards apex and with a distinct or indistinct invagination posteriorly, lancet with spurette (ventrolateral spines), and black head. Anoplonyx males have emarginate clypeus, simple claws, black head and thorax, and distinct penis valves (distinctly expanded ventrally, valvispina clearly extending beyond ventroapical lobe of paravalva, valviceps dorsoapically with hair). Platycampus has an emarginate clypeus, at least a minute subapical tooth of claws, black head and thorax, usually yellow legs, strongly sclerotized lancet with large microdenticles of serrulae and numerous spine-like setae or ctenidia on annuli, and a distinctive penis valve (valvispina not extending beyond ventroapical lobe of paravalva which apically forms a filament, valviceps dorsoapically with hair). Stauronematus, although isolated in its own clade according to genetic data, closely resembles Pristiphora in external morphology, but is distinguished from all other West Palaearctic Nematinae by the large and sharply angled basal lobe of the bifid tarsal claws, with the distance between the basal lobe and the inner tooth approximately equal to the distance between the two teeth.

Females

1. a Hind basitarsus 2–3 times as wide as width of following tarsomere (Fig. 4) b Claws with large subapical tooth close to outer tooth (Fig. 6) c Clypeus emarginate (Fig. 9) d Abdomen nearly always with reddish band, except for some specimens from Ireland ................ ..................................................... (4 species) Nematus septentrionalis group (former Craesus)

– aa Hind basitarsus 1.0–1.5 times as wide as width of following tarsomere (Fig. 5) bb Claws simple or with distinct subapical tooth (Figs 6–8) cc Clypeus emarginate or truncate (Figs 9–10) dd Abdomen with or without reddish band ...................................................................................... 2

2. a Abdominal tergum 9 in lateral view usually more than 3 times as long as tergum 8 (Fig. 11) b Valvula 3 very broad at base or throughout in dorsal view, more than 6 times as broad as width of cercus (Fig. 13) c Lancet strongly sclerotized with spine like setae (Fig. 21) d Left and right mandible both tapered regularly towards apex (Fig. 22) e Clypeus emarginate (Fig. 9) f Claws with distinct subapical tooth (Fig. 6) .......................(7 species) Nematinus Rohwer, 1911

– aa Combination of characters not as in a–f; abdominal tergum 9 in lateral view usually less than 2 times as long as tergum 8 (Fig. 12); valvula 3 narrow or broad in dorsal view, variously shaped; cerci often relatively broader (Figs 14–20); lancet weakly or strongly sclerotized with or without spine-like setae; left and right mandible both tapered regularly towards apex (Fig. 22) or left mandible markedly constricted near middle (Fig. 23) and right mandible tapered regularly towards apex (Fig. 22); clypeus emarginate (Fig. 9) or truncate (Fig. 10); claws simple or with subapical tooth (6–8) ................................................................................................................... 3

3. a Valvula 3 with distinct invagination posteriorly or dorsally (Figs 15–17) ................................... 4

– aa Valvula 3 without distinct invagination posteriorly or dorsally (Figs 14, 18–20) ..................... 10

4. a Claws with long subapical tooth close to apical one (bifid) (Fig. 6) ............................................ 5

– aa Claws simple (Fig. 7) or with large or small subapical tooth clearly separated from apical one (Fig. 8) ......................................................................................................................................... 7

5. a Largely black, pale are at most head ventrally and around eyes, abdomen ventrally and apically, and mesepisternum partly b Valvula 3 with deep invagination (Fig. 16) c In most species, valvula 3 in lateral view angled upwards at about 45° to longitudinal axis of abdomen (Fig. 24) d Setae of lancet absent or weakly developed e Body 3–6 mm ........................................................................................ Euura amentorum group

– aa–ee Combination of characters not as in a–e; from largely black to nearly completely pale; valvula 3 with shallow or deep invagination, but not angled upwards (Fig. 25); setae of lancet present or absent; body 4–8 mm .................................................................................................. 6

6. a Medial surface of head near antennal sockets not markedly elevated in lateral view and slightly or not angular below median pit (head of “ Amauronematus ” type) (Fig. 26) b Clypeus often deeply emarginate (Fig. 9) c Tangium of lancet without campaniform sensilla (Fig. 28) ............ Euura Newman, 1837 in part

– aa Medial surface of head near antennal sockets markedly elevated in lateral view and angular below medial pit (Fig. 27) bb Clypeus usually more or less truncate (Fig. 10) cc Tangium of lancet with campaniform sensilla (Fig. 29) .......... Pristiphora Latreille, 1810 in part

7. a Postocellar area more than 3 times as long as diameter of lateral ocellus (Fig. 30) b Clypeus deeply emarginate (Fig. 9) c Head extensively pale (Fig. 30) d Abdomen nearly completely pale e Hind femur and tarsus black ............................ Euura itoi (Okutani, 1955) (central Europe, rare)

– aa Postocellar area less than 3 (mostly less than 2.5) times as long as diameter of lateral ocellus (Figs 31, 33) bb Clypeus deeply emarginate (Fig. 9) or truncate (Fig. 10) cc Head extensively pale to completely black dd Abdomen pale to black ee Hind femur and tarsus pale to black ............................................................................................ 8

8. a Clypeus deeply emarginate (Fig. 9) b Hypopygium deeply excised (Fig. 32) c Head extensively pale (Fig. 31) ............................................. Euura imperfecta (Zaddach, 1876)

– aa–cc Combination of characters not as in a–c; clypeus deeply emarginate (Fig. 9) or truncate (Fig. 10); hypopygium deeply or not deeply excised; head extensively pale to completely black ..... 9

9. a Clypeus deeply emarginate (Fig. 9) b Body extensively pale c Postocellar area more than 2 times as long as diameter of lateral ocellus d Lancet without setae ...................................................................... Euura epilosa (Lindqvist, 1970) (rare, in Europe so far only known from Bulgaria and Slovakia)

– aa Clypeus usually more or less truncate (Fig. 10) bb Body black to extensively pale cc Postocellar area often less than 2 times as long as diameter of lateral ocellus (Fig. 33) dd Lancet with or without setae .................................................... Pristiphora Latreille, 1810 in part

10.a Transverso-radial (2r-rs) vein usually at least faintly present in forewing (Fig. 34) b Transverso-costal (Sc) vein usually situated beyond or at point of origin of medius (M) from radius (R) (Fig. 34) c Anterior protibial spur without velum, but with hairs (Fig. 35) d Clypeus emarginate e Claws with distinct subapical tooth f Left and right mandible both tapered regularly towards apex (Fig. 22) g Lancet with 11–12 annuli and with thick setae in middle annuli (Fig. 38) .................................... ................................................................................................................. Dineura Dahlbom, 1835

– aa–gg Combination of characters not as in a–g; transverso-radial (2r-rs) vein rarely present in forewing (aberrant individuals) (Fig. 37); transverso-costal (Sc) vein usually situated before point of origin of medius (M) from radius (R) (Fig. 37); anterior protibial spur usually with velum (Fig. 36); clypeus emarginate or truncate; claws with or without subapical tooth; left mandible markedly constricted near middle (Fig. 23) and right mandible tapered regularly towards apex (Fig. 22) in most species; lancet with 8–30 annuli and with or without setae ............................11

11.a Claws simple (Fig. 7) or with small subapical tooth (Fig. 8) .................................................... 12

– aa Claws with large subapical tooth (Fig. 6) .................................................................................. 22

12.a In dorsal view, valvula 3 broad or narrow, not tapering towards apex, truncate, and with indistinct or distinct invagination (Figs 39–41) ........................................................................................... 7

– aa In dorsal view, valvula 3 narrow along its entire length and without invagination (Figs 41–43); or tapering from base towards apex and without invagination (Figs 44–46); or broad, tapering towards apex but not from base, without invagination but with distinct carina posteriorly (Figs 49, 53) .............................................................................................................................................. 13

13.a Flagellum with white band in middle (Fig. 47) b Middle terga of abdomen usually dorsally reddish and laterally whitish (Fig. 47) c Pterostigma black (Fig. 47) d Valvula 3 long and narrow (Fig. 43) e 9.0–11.0 mm .................................................................................. Euura insignis (Hartig, 1840)

– aa Flagellum uniformly black to uniformly pale bb Middle terga of abdomen in most species of similar colour as basal terga cc Pterostigma pale to black dd Valvula 3 variable ee 3.0–11.0 mm .............................................................................................................................. 14

14.a Abdomen with red band, terga 1 and 7–10 black (Fig. 48) b Clypeus truncate c In lateral view, posterior margin of valvula 3 somewhat truncate ................................................. ............................................................................................ Pristiphora erichsonii (Hartig, 1837)

– aa Abdomen without red band bb Clypeus truncate or emarginate cc In lateral view, posterior margin of valvula 3 truncate or round ............................................... 15

15. a In dorsal view, head distinctly expanded behind eyes (Fig. 50) b Valvula 3 with indistinct or distinct carina posteriorly (Fig. 49) c Head and thorax black d Lancet without setae e Tangium with campaniform sensilla ............................ Pristiphora dasiphorae (Zinovjev, 1993) (in Europe only known from Öland, Sweden)

– aa–ee Combination of characters not as in a–e; in dorsal view, head distinctly (Fig. 50) or not distinctly (Fig. 51) expanded behind eyes; valvula 3 with or without carina posteriorly; head and thorax black or pale; lancet with or without setae; tangium with or without campaniform sensilla ....................................................................................................................................... 16

16.a Labrum asymmetrical with right lobe much longer than left (Fig. 52) b Valvula 3 without distinct posterior carina (Fig. 19) c Head, thorax, and abdomen mostly or nearly completely black d Mesepisternum smooth e Claws without subapical tooth f 3.0– 4.5 mm ............................ Pristiphora retusa (Thomson, 1871), P. exigua (Lindqvist, 1955)

– aa Labrum usually symmetrical, or asymmetrical with right lobe slightly longer than left bb Valvula 3 without or with distinct posterior carina cc Head, thorax, and abdomen black to nearly completely pale dd Mesepisternum smooth or matt ee Claws with small subapical tooth in most species ff 3.0–11.0 mm .............................................................................................................................. 17

17.a Valvula 3 about as long as broad in dorsal view and with distinct posterior carina (Fig. 53) b Head, thorax, and abdomen mostly or nearly completely black .................................................... ............................................ Pristiphora angulata Lindqvist, 1974, P. abbreviata (Hartig, 1837)

– aa Valvula 3 with different combination of characters, broad or long, with or without posterior carina bb Head, thorax, and abdomen black to nearly completely pale .................................................... 18

18.a Head, thorax, and abdomen black b Valvifer 2, tergum 10, and clypeus usually black c Metatarsus usually mostly pale d Valvula 3 distinctly shorter than cerci and distinctly tapering towards apex in dorsal view e Mesepisternum matt f Lancet with campaniform sensilla and setae ............................ Pristiphora mollis (Hartig, 1837)

– aa–ff Combination of characters not as in a–f; head, thorax, and abdomen black or pale; valvifer 2, tergum 10, and clypeus black or pale; metatarsus black or pale; valvula 3 longer or shorter than cerci, tapering or not tapering towards apex; mesepisternum smooth or matt; lancet with or without campaniform sensilla and setae .................................................................................... 19

19.a Mesepisternum matt b Clypeus truncate or at most slightly emarginate c Head largely or completely black d Thorax black e Abdomen completely black to extensively pale ventrally, laterally, and apically f Lancet without setae ....................................................................................................................... g Tangium of lancet with campaniform sensilla ........................ Pristiphora carinata group in part

– aa–gg Combination of characters not as in a–f; mesepisternum smooth in most species; clypeus truncate or emarginate; head, thorax, and abdomen black to nearly completely pale; lancet with or without setae; tangium with or without campaniform sensilla ............................................. 20

20.a Clypeus truncate b Postocellar area about 2 times as long as diameter of lateral ocellus c Costa (vein C) apically swollen (Fig. 54) d Serrulae flat (Fig. 56) e Tangium of lancet with campaniform sensilla ........................ Pristiphora abietina group in part, P. wesmaeli (Tischbein, 1853), P. glauca Benson, 1954, P. pallida group, P. tenuiserra (Lindqvist, 1959)

– aa Clypeus usually distinctly emarginate bb Postocellar area often distinctly more than 2 times as long as diameter of lateral ocellus cc Costa (vein C) apically usually less swollen (Fig. 55) dd Serrulae flat (Fig. 56) or protruding (Fig. 57) ee Tangium of lancet without campaniform sensilla (except Euura epilosa, but which has a distinctly emarginate clypeus) ................................................................................................................... 21

21.a Pterostigma black b Body largely black c Lancet without setae d Radix shorter than lamnium e Sutures of lancet indistinctly bending apically f 6.5–7.0 mm .................................................................... Nematus lonicerae (Weiffenbach, 1957)

– aa–ff Combination of characters not as in a–f; pterostigma pale in most species; body pale to black; lancet with or without setae; radix shorter, longer than or about as long as lamnium; sutures of lancet not bending apically, or bending indistinctly or distinctly; 3–9 mm .................................. ........................................................................................................ Euura Newman, 1837, in part

22.a Clypeus more or less truncate b Postocellar area less than 2 times as long as diameter of lateral ocellus c Valvula 3 about as broad as long in dorsal view, somewhat square-shaped, often with invagination posteriorly d Costa (vein C) apically swollen (Fig. 54) e Lancet with setae f Tangium of lancet with campaniform sensilla g 4–7 mm .................................... Pristiphora depressa group and P. micronematica group in part

– aa Clypeus usually distinctly emarginate bb Postocellar area often distinctly more than 2 times as long as diameter of lateral ocellus cc Valvula 3 in most species triangular in dorsal view, usually without invagination posteriorly dd Costa (vein C) apically usually less swollen (Fig. 55) ee Lancet with or without setae ff Tangium of lancet without campaniform sensilla (except Euura epilosa, but which has distinctly emarginate clypeus) gg 2.5–12.0 mm .............................................................................................................................. 23

23.a Mesepisternum matt b Terga (1–)2–3(–6), femora, tibiae, and tarsi of fore and middle legs reddish (Fig. 58) c Pterostigma black d Body 7–11 mm, elongate appearance with abdomen tapering almost from base .......................... .................................................................................................... Nematus lucidus (Panzer, 1801)

– aa Mesepisternum smooth or matt bb Colouration different cc Pterostigma black or pale dd Body 2.5–12.0 mm, usually not markedly elongate or with abdomen tapering from base ....... 24

24.a Pronotal angles black (Fig. 59) b Abdomen black with 3rd and 4th segment more or less pale (Fig. 59) c Pterostigma black d Body 8–12 mm ........................................................................ Nematus princeps Zaddach, 1876

– aa Pronotal angles black or pale bb Abdomen colouration different cc Pterostigma black or pale dd Body 2.5–11.0 mm .................................................................................................................... 25

25.a Pterostigma black (Fig. 60) b Costa largely (usually?) black c Head black d Abdomen yellow (Fig. 60) e In dorsal view, valvula 3 short and somewhat expanded in middle f Lancet with 13–16(17?) annuli, all with serrulae, and radix shorter than lamnium g Body 5.0– 7.5 mm ................................................................. Nematus umbratus Thomson, 1871

– aa–gg Combination of characters not as in a–g; pterostigma pale to black; costa pale to black; head nearly completely pale to black; abdomen pale to black; valvula 3 triangular in most species; lancet with 13–30 annuli and radix shorter or longer than lamnium; body 2.5–11.0 mm ......... 26

26.a Pterostigma black or dark brown b Head, thorax, and abdomen largely black c Valvula 3 narrowed at apex d Radix shorter than lamnium e Setae of lancet absent or short and not reaching serrulae (Fig. 63) f Tips of serrulae blunt (Fig. 63) g Body 5.5–9.5(10.5) mm ...................................................................... Nematus wahlbergi group (including N. lonicerae) (former Paranematus)

– aa–gg Combination of characters not as in a–g; pterostigma pale to black; head, thorax, and abdomen black to pale; valvula 3 narrowed or not narrowed at apex; radix shorter or longer than lamnium; setae of lancet present, long or short and reaching serrulae at least on apical sutures; tips of serrulae blunt or acute; body 2.5–11.0 mm .......... Euura Newman, 1837, in part (more than 200 species)

Males

1. a Hind basitarsus 2–3 times as wide as width of following tarsomere b Claws with distinct subapical tooth (Fig. 6) c Clypeus emarginate (Fig. 9) d Abdomen nearly always with reddish band in Europe .................................................................. ....................................................... (4 species) Nematus septentrionalis group (former Craesus)

– aa Hind basitarsus 1.0–1.5 times as wide as width of following tarsomere bb Claws simple (Fig. 7) or with distinct subapical tooth (Figs 6, 8) cc Clypeus emarginate (Fig. 9) or truncate (Fig. 10) dd Abdomen with or without reddish band ...................................................................................... 2

2. a Transverso-radial (2r-rs) vein usually at least faintly present in forewing (Fig. 34) b Transverso-costal (Sc) vein usually situated beyond or at point of origin of medius (M) from radius (R) (Fig. 34) c Anterior protibial spur without velum, but with hairs (Fig. 35) d Clypeus emarginate (Fig. 9) e Claws with distinct subapical tooth f Tergum 8 without distinct apical projection g Valvispina straight, not hook-shaped (Fig. 61) h Paravalva apically filament-like (Fig. 61) .............................................. Dineura Dahlbom, 1835

– aa–hh Combination of characters not as in a–h; transverso-radial (2r-rs) vein rarely present in forewing (aberrant individuals) (Fig. 37); transverso-costal (Sc) vein usually situated before point of origin of medius (M) from radius (R) (Fig. 37); anterior protibial spur usually with velum (Fig. 36); clypeus emarginate (Fig. 9) or truncate (Fig. 10); claws with or without subapical tooth; tergum 8 with or without distinct apical projection; valvispina variously shaped; paravalva apically not filament-like in most species .................................................................................... 3

3. a Pseudoceps often with distinct apical filament, sometimes longer than valvispina b Paravalva (often filament-like) distinctly extending apically from base of valvispina, sometimes beyond its tip (Fig. 62) c Clypeus emarginate d Claws with distinct subapical tooth e Tergum 8 with rounded distinct or indistinct apical projection (Fig. 64) ...................................... ............................................................................................................... Nematinus Rohwer, 1911

– aa–ee Combination of characters not as in a–e; pseudoceps in vast majority of species apically not filament-like; paravalva extending (Fig. 67) or not extending apically from base of valvispina (Fig. 68), in few species valvispina absent; clypeus truncate or emarginate; claws with or without subapical tooth; tergum 8 with or without apical projection ....................................................... 4

4. a Claws with large subapical tooth ................................................................................................. 9

– aa Claws simple or with small subapical tooth ................................................................................ 5

5. a Flagellomere 1 black and flagellomeres 2–7 more or less pale b Pterostigma black c Tergum 8 with distinct apical projection d 8.0–10.0 mm .................................................................................. Euura insignis (Hartig, 1840)

– aa Flagellum uniformly black to uniformly pale bb Pterostigma pale to black cc Tergum 8 with or without distinct apical projection dd 2.0–10.0 mm ................................................................................................................................ 6

6. a Tergum 8 with distinct apical projection (Fig. 66) b Clypeus usually distinctly emarginate c Costa (vein C) apically usually not distinctly swollen ................................................................ 8

– aa Tergum 8 without distinct apical projection (Fig. 65) bb Clypeus usually truncate cc Costa (vein C) apically usually distinctly swollen ...................................................................... 7

7. a Head, thorax, and abdomen mostly black b Costa not distinctly expanded c Penis valve with deep invagination between valvispina and paravalva (Fig. 67) ......................... ...................................................................................................... Euura moerens (Förster, 1854)

– aa Head, thorax, and abdomen black to extensively pale bb Costa usually distinctly expanded cc Penis valve without or almost without invagination between valvispina and paravalva or valvispina rarely absent .......................................................... Pristiphora Latreille, 1810, in part

8. a Pterostigma black b Head, thorax, and abdomen mostly black c Legs extensively whitish d Sternum 9 and tergum 8 including its apical projection black e Apical projection of tergum 8 distinctly constricted at base (Fig. 66) f 5.5–6.0 mm .................................................................... Nematus lonicerae (Weiffenbach, 1957)

– aa–ff Combination of characters not as in a–f; pterostigma pale to black; head, thorax, and abdomen black to nearly completely pale; legs black to pale; sternum 9 and tergum 8 including its apical projection black or pale; apical projection of tergum 8 constricted or not constricted at base; 2.0–10.0 mm .................................................................................. Euura Newman, 1837, in part

9. a Clypeus truncate b Head, thorax, and abdomen black c Antennae ventrally distinctly paler than dorsally or uniformly yellow and with numerous and clearly visible stout black setae among finer paler ones (Fig. 70) d Apical projection of tergum 8 longer than broad (Fig. 69) e Paravalva strongly reduced (Fig. 71) f Valvispina large and strongly dorsally curved (Fig. 71) ................................................................ ............................................... Pristiphora armata (Thomson, 1862), P. leucopus (Hellén, 1948)

– aa–ff Combination of characters not as in a–f; clypeus truncate or emarginate; head, thorax, and abdomen extensively pale to black; antenna pale to black and with or without clearly visible stout black setae among finer paler ones; apical projection of tergum 8 variously shaped or not clearly developed; paravalva strongly reduced or well developed; valvispina variously shaped or absent in few species ............................................................................................................................. 10

10.a Pseudoceps with dorsal membranous region covered with setae (Fig. 72) b Valvispina not clearly developed (Fig. 72) c Apical projection of tergum 8 indistinct d Clypeus usually truncate e Head, thorax, and abdomen black .............................. Pristiphora micronematica group, in part

– aa Pseudoceps without membranous region covered with setae (Fig. 73) bb Valvispina clearly developed in most species cc Apical projection of tergum 8 distinct or indistinct dd Clypeus truncate or emarginate ee Head, thorax, and abdomen extensively pale to black ...............................................................11

11.a Valvispina positioned in middle or dorsal third of paravalva (Fig. 73) b Invagination between valvispina and ventral part of paravalva absent (Fig. 73) c Valvispina medium sized, not distinctly expanded at base and straight or directed slightly dorsally (Fig. 73) d Pseudoceps broad at apex (Fig. 73) e Paravalva rectangular or oval-shaped (Fig. 73) f Apical projection of tergum 8 indistinct g Clypeus truncate h Claws not bifid i Head and abdomen ventrally usually pale, sometimes also thorax j Legs usually mostly pale, except hind tarsus and hind tibia and/or femur apically ...................... ................................ Pristiphora pallidiventris (Fallén, 1808) and P. cadma Wong & Ross, 1960

– aa–jj Combination of characters not as in a–j; valvispina positioned in most species dorsally or ventrally, absent in a few species; invagination between valvispina and ventral part of paravalva absent or present; valvispina small to large, straight or directed dorsally or ventrally; pseudoceps broad or narrow; paravalva variously shaped; apical projection of tergum 8 distinct or indistinct; clypeus truncate or emarginate; claws bifid or with large subapical tooth; head, thorax, and abdomen extensively pale to black; legs mostly pale to black .................................................. 12

12.a Valvispina positioned ventrally of paravalva (Fig. 74), if appearing in middle, then bending dorsally together with ventral part of paravalva b Invagination between valvispina and ventral part of paravalva absent (Fig. 74) c Paravalva well developed and pseudoceps broad at apex, or paravalva strongly modified to large dorsally directed valvispina and pseudoceps often narrowing apically (Fig. 74) d Apical projection of tergum 8 indistinct e Clypeus usually truncate f Claws rarely bifid ................................................................................ Pristiphora Latreille, 1810

– aa–ff Combination of characters not as in a–f; valvispina positioned in middle or dorsally of paravalva (Figs 75–78), absent in a few species; invagination between valvispina and ventral part of paravalva often present; paravalva well developed and valvispina small to large, rarely directed dorsally (Figs 75–78), pseudoceps broad or distinctly narrowing, sometimes forming a filament or spine; apical projection of tergum 8 distinct in most species; clypeus usually emarginate; claws usually bifid ............................................................................................................................... 13

13.a Mesepisternum matt b Terga (1–)2–3(–6), pronotal angles, femora, tibiae, and tarsi of fore and middle legs reddish c Pterostigma black d Body 7–10 mm, torpedo-shaped e Invagination between valvispina and paravalva wide and deep (Fig. 75) f Pseudoceps apically broad ......................................................... Nematus lucidus (Panzer, 1801)

– aa–ff Combination of characters not as in a–f; mesepisternum smooth or matt; colouration different in most species; pterostigma black or pale; body 2.0–10.0 mm, usually not torpedo-shaped; invagination between valvispina and paravalva distinct or absent; pseudoceps apically broad or distinctly narrowing ................................................................................................................... 14

14.a Pronotal angles black b Abdomen black, sometimes with 3rd and 4th segment more or less pale c Hind tibia and tarsus black d Pterostigma black e Body 8–10 mm, torpedo-shaped f Valvispina with distinct ventral hook (Fig. 76) ....................... Nematus princeps Zaddach, 1876

– aa Pronotal angles black or pale bb Abdomen black to pale cc Hind tibia and tarsus black to pale dd Pterostigma black or pale ee Body 2.0–10.0 mm, not torpedo-shaped ff Valvispina simple, without hook, or absent in few species ....................................................... 15

15.a Pterostigma black b Costa largely (usually?) black c Head black d Abdomen usually at least ventrally yellow e Ventroapical lobe of paravalva extending about one third of the length of valvispina (Fig. 77) f Basal third or half of valvar strut more or less at the ventral margin of paravalva (Fig. 77) g Dorsobasal part of paravalva narrowing abruptly (Fig. 77) h Body 4.0– 6.5 mm ................................................................. Nematus umbratus Thomson, 1871

– aa–hh Combination of characters not as in a–h; pterostigma pale to black; costa pale to black; head nearly completely pale to black; abdomen pale to black; ventroapical lobe of paravalva variously shaped, valvispina absent in some species; basal third or half of valvar strut often distinctly removed from ventral margin of paravalva (Fig. 78); dorsobasal part of paravalva narrowing abruptly or gradually; body 2.0–10.0 mm ................................................................................. 16

16.a Pterostigma black or dark brown b Head, thorax, and abdomen largely black c Legs extensively whitish or reddish d Sternum 9 and tergum 8 black e Penis valve oval-shaped, pseudoceps apically not distinctly narrowed, small invagination between valvispina and paravalva, dorsal and apical margin of pseudoceps strongly and broadly sclerotized (Fig. 78) f Body 5.0– 7.5 mm ... Nematus wahlbergi group (including N. lonicerae) (former Paranematus) (males of the species other than N. lonicerae are extremely rare in the West Palaearctic)

– aa–ff Combination of characters not as in a–f; pterostigma pale to black; head, thorax, and abdomen black to pale; legs black to pale; sternum 9 and tergum 8 black or pale; penis valve differently shaped; body 2.0–10.0 mm ..................... Euura Newman, 1837, in part (more than 200 species)