Ophion Fabricius 1798, sp. nov.

Genus Ophion Fabricius, 1798

In this study, more than 4800 specimens representing 41 species were studied. Eighteen species are described as new to science: Ophion angularis Johansson & Cederberg sp. nov., Ophion arenarius Johansson sp. nov., Ophion autumnalis Johansson sp. nov., Ophion borealis Johansson sp. nov., Ophion broadi Johansson sp. nov., Ophion brocki Johansson sp. nov., Ophion confusus Johansson sp. nov., Ophion ellenae Johansson sp. nov., Ophion inclinans, Johansson sp. nov., Ophion kallanderi Johansson sp. nov., Ophion matti Johansson sp. nov., Ophion norei Johansson sp. nov., Ophion paraparvulus Johansson sp. nov., Ophion paukkuneni Johansson sp. nov., Ophion splendens Johansson sp. nov., Ophion sylvestris Johansson sp. nov., Ophion tenuicornis Johansson sp. nov. and Ophion vardali Johansson sp. nov. Eleven species are documented from Sweden for the first time; Ophion artemisiae, Ophion crassicornis, Ophion costatus, Ophion dispar, Ophion forticornis, Ophion kevoensis, Ophion ocellaris, Ophion perkinsi, Ophion subarcticus, Ophion variegatus and Ophion wuestneii.

Barcoding results

234 specimens produced barcodes (out of an attempted 284) (Fig. 1). A full barcode sequence (658 bp) was recovered from 115 specimens, sequences greater than 500 bp from 95 specimens and shorter sequences from 24 specimens. Specimens included in the analysis with a barcode shorter than 500 bp is marked with an * in Fig. 1. Full length barcodes or barcodes with more than 630 bp, were recovered from at least one specimen for all species except O. obscuratus, O. autumnalis Johansson sp. nov. and O. kallanderi Johansson sp. nov. A sequence from O. vardali Johansson sp. nov. containing 401 bp was acquired from NorBOL project DS-ICHNN. No Swedish specimens of O. forticornis and O. subarcticus were sequenced due to the absence of material suitable for sampling. An additional sequence from Ophion forticornis retrieved from the dataset of Schwarzfeld et al. (2016) at https://datadryad.org/resource/doi:10.5061/dryad. 49g 98 was included in the phylogenetic analysis. Barcode records for the sampled specimens are available in the BOLD dataset “STI-NJBC”. The barcoding in combination with the morphological analysis confirms and supports the existence of a majority of the species defined in this study and indicates the existence of at least three additional potentially cryptic species (Fig. 1). The sequencing also supports the aggregate nature of several species by small, but consistent genetic differences. This particularly concerns the aggregates around Ophion luteus (Fig. 3), O. perkinsi (Fig. 4) and O. inclinans Johansson sp. nov. (Fig. 5).

Assessment of morphological characters used in species delimitation

When it comes to morphological characters used in definition and separation of species, there are some new characters highlighted in this study that have been used in combination with more well known features used by previous authors to delimit species.

Body size

The size of the body is a character that can be used to identify some species in combination with other morphological features. As the metasoma often is bent in various postitions the size is usually indicated by the length of the fore wing. There is always some variation in size between individuals and frequently unusally small specimens are encountered. These are probably either the result of starved specimens or specimens reared from smaller host-species.

Head

The distance from the outer margin of the lateral ocellus to the nearest inner margin of the compound eye (the ocellar-ocular interspace) (Figs 14 A–B, 18A–B) has been regarded as an important feature by several previous authors (Gauld 1973; Brock 1982; Broad 2012). The ocellar-ocular interspace is somewhat variable within species but in many species quite characteristic, indeed making it a rather useful character in species separation. The ocellar-ocular interspace often has a relation to the length of the temple/the length of the compound eye ratio, which is another useful feature (Figs 15 E–G, 19B, D, F). The importance of this character has been underestimated by previous authors. While the shape and the length of the temple usually is assessed in dorsal view, this perspective and the percieved length of the temple can be strongly affected by only a slight change in the angle of view. A lateral view is often a better way to appreciate the ratio. The length of the malar space, i.e., the shortest distance between the lower margin of the compound eye to the mandibular base, in relation to the width of the mandibular base, is often used in species definition (Jussila 1965; Brock 1982). It is a quite consistent character within species, though sometimes hard to appreciate in detail and seemingly more variable in males than in females. The sulcus, i.e., the elongate groove, behind the lateral ocelli (Fig. 15B), can be diagnostic. In some species it is particularly well defined and useful as a complementary character in species definition (Brock 1982). The importance of the shape of the occipital carina (Fig. 7 A–B) has been partly overlooked by previous authors and is quite useful in species definition, mainly used in combination with other characters. Dorsally it can be angled, medially dipped or straight. Also the shape of occipital carina before the junction beween the occipital and hypostomal carina can be useful for some closely related species pairs (Izquierdo 1984).

A feature which is very useful, but rarely previously used to any extent in the diagnosis of Ophion species, is the shape of the head in anterior view and the relation between the width of the face and the compound eye, often also supported by the shape of the clypeal area (Schwarzfeld & Sperling 2014). As the shape of the temples treated above, the importance of this character has been obscured by the aggregate nature of some species. The human ability of facial recognition can be a valuable asset when trying to separate closely related species. The sculpture of the face, i.e., the intensity and size of the punctation and the surface being more or less shagreened, is a somewhat variable character in many species, but nevertheless very useful in defining morphospecies if treated in combination with other characters.

The mandibular gape, i. e. the angle between the two mandibular teeth (Fig. 7 H–I), is useful in separating some closely related species in some subgroups, but only when exhibiting a distinct difference, i.e., the gape forming an acute angle vs an obtuse or right angle (Morley 1915; Brock 1982; Broad 2012; Broad et al. 2015;). A secondary character to be noted is that species attacking hosts pupating under ground often have the mandibles more or less worn from emerging through soil, indicating an ecological characterization that sometimes can be useful in indicating the species involved.

Antennae

The length and shape of the flagellomeres and the number of flagellomeres has been shown to be of significance in the separation of species in some aggregates (Figs 7 N–O, 8A–F, 8M–O). The number of flagellomeres, though slightly variable within species, seems to be a good way to delimit species groups and sometimes also closely related species (Brock 1982; Broad 2012). The relative length and width of the flagellomeres, as well as the pilosity of the flagellomeres seem to be quite consistent within some species and also between the sexes.

Mesosoma

The structure of the mesoscutum and mesopleuron is often quite typical, but not particularly often previously used for the separation and definition of species. Although variable to some extent within species, it is diagnostic in others and sometimes also useful in separating closely related species. The length of the scutellar carinae (Fig. 6 A–D) have been of taxonomic importance primarly to separate species within the wider definition of the O. luteus group as defined by Gauld (1985). The extension of the carinae can be slightly variable within species but it is still an important character for species definition (Thomson 1888; Brock 1982; Gauld 1978). The shape of the scutellum in dorsal, and sometimes lateral view, can also contribute to the determination. The sides of the scutellum can be more or less converging and the scutellum more or less convex in lateral view.

A very useful character when it comes to definition of morphospecies is the shape of the epicnemial carina (Brock 1982; Broad 2012). The shape of the pleurosternal angles and their position in relation to the sternal angles in anteroventral view (Fig. 9 A–I) is often typical and relatively constant within species groups or sometimes within single species (Brock 1982; Broad 2012). Another characteristic that can be used in species diagnostics is the shape of the propodeal carinae (Figs 10 A–O, 14C–D, 18E–F). The carinae can be more or less well developed in single individuals, but the interspace and angles between the carinae are quite consistent within species. Due to the individual variation in the development of the carinae, its taxonomic use has been somewhat underestimated.

Wings

The presence/absence and relative length of the ramellus in the fore wing (Fig. 16 A–B) and the nervellus in the hind wing being broken at, above or below the middle by the discoidella (Fig. 13 E–F) have been used by previous authors (Brock 1982; Broad 2012; Broad et al. 2015) and especially the latter can be useful in the separation of species. Brock (1982) regards this character as unstable and thereby less useful, which is the result of the misinterpretation of some species by the author. The shape of the radius in the fore wing can be diagnostic as it can be evenly curved or more or less sinuous (Fig. 13A, C). This character seem to be more stable in females than in males.

Legs

The shape of the legs, e.g., the ration between the length and the width of the femur, tarsus and trochantellus, is often useful in separating som species or species groups (Gauld 1978; Brock 1982). Notable is also the length of the hind tibial spurs in relation to the length of the hind metatarsus (Brock 1982).

Metasoma

A character that is particularly useful when defining species is the relative positioning of the spiracle of the first tergite in relation to the hind margin of the sclerotised section of the first sternite (Fig. 6 E–H) (Brock 1982; Broad 2012). The spiracle can be situated level with, or more or less posterior to the hind margin on the sclerotised part of the sternite. Some variability in this character will usually make it necessary to combine it with other characters, such as the carination of the lateral margins of the scutellum. The shape of the first tergite in lateral view (Fig. 20 E–F) as well as the prescence or absence of a dorsal undulation is also quite consistent and useful. The shape of the male genitalia is usually quite similar between species and parameres are often deformed by being stored in ethanol or if dried up. However, in some cases the shape of the parameres in lateral view can be useful in the separation of species (Fig. 6 I–J).

Colour

Even though known for their lack of diagnostic colouration, there are some colour characters in Ophion that can provide information regarding the identification of certain species. The colouration of the head, mesosoma and metasoma have been used to primarily define species with extensive black or pale markings. For some species groups, the colour of the ovipositor sheath is a very useful distinguishing character used in this study. The colour of the stemmaticum can be of some importance when separating the two species within the subgenus Platophion Hellén, 1926. While the darker or brownish colouration of the mesosoma and coxae in some species can be rather variable it is found to be quite constant in others, thereby being partly diagnostic. In some species more subtle colour characters, such as the prescence/absence or the distribution of the paler areas around the compound eyes and scutellum, can provide some information that can contribute to species diagnostics.

Identification key to the Swedish species of Ophion

The key is constructed primarily to key out females (ovipositor present). In many cases both sexes can be keyed out, but generally males are less distinct when it comes to characters useful in separating species (the shape of the pleurosternal angles, head, flagellomeres etc.) and sometimes there is no satisfactory way to identify males with accuracy. It is important to bear in mind that all characters display some degree of variation and used individually they will often be found to overlap between species. It is therefore crucial that all determination of Ophion species (apart from a couple of distinct species) focus on the species’ unique combination of characters. This of course has implications for the construction of a useful key. If one is to cover every possible aspect of variation within species, the key would end up an uncrossable marsh of ‘or’s’ and ‘and’s’ and ‘if’s’. It shall therefore be stated that the key presented here is simplified to some extent, but still fully sufficient for determining a majority of specimens. It is also necessary, if one is to determine specimens with accuracy, to build a reference collection of correctly determined material.

1. Occipital carina entirely absent centrally, at most weakly defined laterally (Fig. 7 C–D); wing membrane strongly yellowish; scutellum rectangular without lateral carinae (Fig. 6B); epicnemial carina with pleurosternal and sternal angles indistinct (Fig. 9H)..................................................... 2

– Occipital carina present (Fig. 7 A–B); wing membrane rarely strongly yellowish (but see O. ventricosus – couplet 3), usually colourless; scutellum with or without lateral carinae, narrowed apically (Fig. 6A, C–D); epicnemial carina with at least pleurosternal angles usually more prominent (Fig. 9 A–B, E–G, I).......................................................................................................................... 3

2. Stemmaticum black or dark brown; antenna with more than 50 flagellomeres; occipital carina completely absent (Fig. 7C); area superomedia usually absent with transverse wrinkles in its place (Fig. 10I); female with metasoma shorter, tergites 4–5 in lateral view about 1.5 times as wide as long; spiracles on 4–5 th tergites closer to the base of the tergite (Fig. 8L); male with parameres elongate and evenly rounded in lateral view........................................... O. ocellaris Ulbricht, 1926

– Stemmaticum testaceous, concolourous with head, very rarely brownish; antenna with fewer than 50 flagellomeres; occipital carina present laterally (Fig. 7D); area superomedia often well-defined, in the shape of a small arc (Fig. 10J); female with metasoma longer, tergites 4–5 almost square in lateral view; spiracles situated more or less at the center of the tergite (Fig. 8K); male with parameres stout and dorsally flattened in lateral view................................................ O. areolaris Brauns, 1889

3. Head and mesosoma with conspicuous black marks and patches (Fig. 11 C–D); wing membrane strongly yellowish......................................................................... O. ventricosus Gravenhorst, 1829

– Body usually without conspicuous black marks; wing membrane at most weakly yellowish. If the mesosoma displays fuscous or black areas, these are not forming distinct patterns as in Fig. 11 C–D and the head has no black markings................................................................................................. 4

4. A small species (fore wing length 7–11 mm); mesosoma in male with rich pale markings and in female more often uniformly testaceous with posterior segments of metasoma often infuscate and scutellum and head extensively yellow marked; propodeum largely without carinae, only posterior transverse carina indicated laterally; vein Rs+2 r usually distinctly thickened and curved at junction with pterostigma (Fig. 12).............................................................. O. minutus Kriechbaumer, 1879

– Usually larger species (fore wing length more than 12 mm); propodeum usually with distinct carination; radius not distinctly thickened or curved at junction with pterostigma (Fig. 13 A–D)... 5

5. Propodeum with carinae complete and posterior transverse carina strongly raised (Fig. 10O); mesosoma with extensive pale markings (as in Fig. 11 A–B); head strongly buccate; antenna with fewer than 50 flagellomeres. A very rare species occurring in sand dunes in Southern Sweden.................................................................................................... O. forticornis Morley, 1915

– Propodeum with carinae usually not strongly raised; if mesosoma has pale markings, then carinae of propodeum are not strongly raised and the antenna has more than 50 flagellomeres...................... 6

6. Sclerotised section of first sternite ending level with or slightly posterior to the spiracle (Fig. 6 G–H); scutellum with lateral carinae at most indicated anteriorly (Fig. 6A), rarely (in O. luteus, O. subarcticus, O. kevoensis, O. slaviceki and O. crassicornis) covering the anterior half or more of the scutellum; ovipositor sheath testaceous, concolourous with posterior metasomal segments, or brown–black, contrasting in colour with posterior metasomal segments......................................... 7

– Sclerotised section of first sternite ending distinctly posterior to spiracle (Figs 6 E–F, 20E–F) (the exceptions are O. artemisiae, a species with wrinkled mesopleuron and ramellus absent (Fig. 24 A–B), and O. longigena, a distinct species with strongly buccate head (Fig. 35 A–B); scutellum with lateral carinae always distinct in at least anterior half (Fig. 6C); ovipositor sheath always testaceous–brown, concolourous with posterior metasomal segments......................................................................... 28

7. Antenna with 50 or fewer flagellomeres; central flagellomeres in female short, square (Fig. 8M), slightly longer in males; head strongly buccate with distinct gap between lateral ocellus and compound eye (Fig. 18A); malar space about 0.5 times as wide as mandibular base; head and mesosoma evenly testaceous, never with yellow markings on mesosoma or distinctly paler areas around the eyes...................................................................................... O. brevicornis Morley, 1915

– Antenna usually with 50 or more flagellomeres, if rarely with fewer than 50 flagellomeres, then the central flagellomeres are distinctly longer than wide (compare with Fig. 8 N–O); malar space usually distinctly shorter than 0.5 times as wide as mandibular base........................................................... 8

8. Epicnemial carina, in antero-ventral view, with pleurosternal angles rounded, distinctly anterior to sternal angles (Fig. 9 D–E, I); pleurosternal angles obtuse or right-angled, very rarely slightly acute; anterior transverse carina of propodeum often complete (Fig. 10A, L); first flagellomere more than 3.5 times as long as wide; ovipositor sheath in all but one species (O. sylvestris Johansson sp. nov.) testaceous–brown, usually concolourous with posterior metasomal segments (note that the females of O. costatus and O. tenuicornis Johansson sp. nov. usually have the ovipositor sheath brownish, slightly contrasting with the posterior metasomal segments)........................................................... 9

– Epicnemial carina, in antero-ventral view, with pleurosternal angles more conspicuous, in most cases in level or slightly anterior to sternal angles (Fig. 9 A–B, F–G); pleurosternal angles acute or rightangled, rarely obtuse; anterior transverse carina of propodeum often weak laterally (Fig. 10 D–E, H, M); first flagellomere usually about 3.0 times as long as wide; ovipositor sheath always black or dark brown, contrasting distinctly in colour with the more testaceous posterior segments of metasoma........................................................................................................................................ 22

9. Fore wing with radius evenly curved (Fig. 13A); posterior transverse carina of propodeum often complete, sometimes narrowly interrupted in the middle (Fig. 10B); head with lateral ocellus touching eye; hind trochantellus short, in dorsal view almost obscured by trochanter (Fig. 7G); antenna frequently with fewer than 50 flagellomeres..................................................................... 10

– Fore wing with radius sinuous (Fig. 13C); posterior transverse carina of propodeum usually widely interrupted in the middle; hind trochantellus usually longer in dorsal view (Fig. 7 E–F); antenna rarely with fewer than 50 flagellomeres......................................................................................... 13

10. Antenna very narrow; flagellomeres 2–4 strongly elongate, about 3.5–4.0 times as long as wide; subapical flagellomeres about 2.5–3.0 times as long as wide, in females with long prominent pilosity (Fig. 8C); anterior transverse carina of propodeum strongly raised and evenly curved (Fig. 10L); head in female in lateral view with temples short (as in Fig. 19F). Active in late summer/autumn in Sweden.......................................................................................... O. tenuicornis Johansson sp. nov.

– Antenna stouter; subapical flagellomeres, at most 2.0 times as long as wide (Fig. 8 A–B); head in female in lateral view with temples usually slightly longer (as in Fig. 19D)...................................11

11. Hind tarsal segments stout, fourth segment usually about 2.0 times as long as wide, fifth segment slightly longer than fourth (Fig. 8H); mid-tarsus with fourth segment stout, 0.6 times as long as fifth segment; apical flagellomeres in females usually with long prominent pilosity (as in Fig. 8B); posterior transverse carina of propodeum strong; indicated area superomedia often with a central longitudinal fold (Figs 10B, 47 A–B). Usually a large and stout species (fore wing length 18–19 mm) with slightly infuscate areas on mesosoma and weakly yellowish wing membrane. A late summer/ autumnal species in Sweden.................................................................. O. costatus Ratzeburg, 1848

– Hind tarsus slender and elongate; fourth segment about 3.0 times as long as wide; fifth segment as long as fourth (Fig. 8G); mid-tarsus with fourth segment more slender 0.8–0.9 times as long as fifth segment; posterior transverse carina of propodeum sometimes reduced centrally. Usually smaller species with transparent wing membrane. Two early summer/summer species in Sweden........... 12

12. Flagellomere 30 onwards elongate, about 1.8–1.9 times as long as wide (Fig. 8B); posterior transverse carina of propodeum usually widely interrupted or weak centrally; head in lateral view with temple about 0.3 times as long as compound eye (as in Fig. 19F)........ O. paraparvulus Johansson sp. nov.

– Flagellomere 30 onwards at most 1.5 times as long as wide, with short pilosity (Fig. 8A); posterior transverse carina of propodeum usually complete or only narrowly interrupted centrally; head in lateral view with temple about 0.4–0.5 times as long as compound eye in lateral view (as in Fig. 19D)........................................................................................ O. parvulus Kriechbaumer, 1879

13. Hind trochantellus as long as, or slightly longer than wide in dorsal view (Fig. 7E); mandibular gape more or less acute; internal angles weak or absent (Fig. 7I), teeth often worn, obtuse; mesosoma rarely in Swedish specimens with pale markings (Note that specimens of Ophion luteus frequently occurs with mandibles with distinct internal angles. These specimens may run out as Ophion kevoensis but has the temples more buccate and is active earlier in the season).................................................. 14

– Hind trochantellus shorter than wide in dorsal view (Fig. 7 F–G); mandibular gape right-angled, with internal angles (Fig. 7H); mesosoma and often also metasoma in the most common species with conspicous pale markings (Fig. 11 A–B)......................................................................................... 15

14. Smaller species (fore wing 12–15 mm); head with ocelli small and distinct gap between lateral ocellus and eye of about 0.4–0.5 times the diameter of ocellus; temple in female buccate with distinct space between compound eye and lateral ocellus (Fig. 14A); male usually with temples testaceous. A rather rare but widespread spring/early summer species..................... O. luteus (Linnaeus, 1758)

– Larger species (fore wing 14–17 mm); head with ocelli large and usually touching or almost touching inner margin of compound eye; temple in female slightly shorter (Fig. 14B); male usually with temples more or less yellow. A common species in open or semi-open localities in Southern Sweden during late summer.......................................................... O. slaviceki Kriechbaumer, 1892 stat. rev.

15. Mesosoma with extensive pale markings(Fig. 11 A–B);temple in lateral view quite buccate in both sexes; face in females wide, about 2.0 times the width of compound eye in anterior view (Fig. 17A)........ 16

– Mesosoma without pale markings; head often narrowed behind eyes but sometimes strongly buccate (Fig. 18B).............................................................................................................................................. 17

16. Larger species (fore wing 16–18 mm); antenna with more than 60 flagellomeres; central flagellomeres in males 1.3–1.5 times as long as wide (Fig. 7N); occipital carina joining hypostomal carina at an angle of 45 degrees (Fig. 7L); scutellum usually wider posteriorly. Active during late autumn in Southern Sweden...................................................................... Ophion obscuratus Fabricius, 1798.

– Smaller species (fore wing 14–16 mm); antenna usually with 60 or fewer flagellomeres; central flagellomeres in males 1.5–1.6 times as long as wide (Fig. 7O); occipital carina joining hypostomal carina at an angle of 80–90 degrees (Fig. 7M); scutellum usually more narrowed posteriorly. Active during early summer........................................................ Ophion variegatus Rudow, 1883 stat. rev.

17. Temple strongly bucccate with distinct gap between lateral ocellus and compound eye of 0.5–0.7 the diameter of ocellus (Fig. 18B); malar space long (Fig. 18D); mesopleuron between punctures shagreened, irregularly wrinkled; mesosoma more brownish, contrasting in colour with the more testaceous metasoma (Fig. 42). A very rare species in the subalpine areas of central Sweden................................................................................................... O. subarcticus Hellén, 1926

– Temple narrowed behind eyes; gap between lateral ocellus and compound eye at most 0.3 times the diameter of ocellus; malar space short; mesopleuron between punctures often polished, smooth; mesosoma testaceous or brownish, concolourous with metasoma................................................. 18

18. Antenna with 50 or fewer flagellomeres; second flagellomere 3.0 times as long as wide; hind trochantellus short (Fig. 7G); pleurosternal angles slightly protuding and acute (Fig. 9I); anterior transverse carina of propodeum evenly curved (as in Fig. 10L). Note that the male of this species always seems to have the radius evenly curved while it is weakly sinuate in the female............................................................................................. O. kallanderi Johansson sp. nov.

– Antenna with more than 52 flagellomeres; second flagellomere 1.5–2.0 times as long as wide; hind trochantellus usually longer (Fig. 7F); pleurosternal angles obtuse or right angled; anterior transverse carina of propodeum slightly angled (as in Fig. 10A).................................................................... 19

19. Head of female in anterior view with face narrow (Figs 16F, 17B)............................................... 20 – Head of female in anterior view with face wide (Figs 16E, 17A).................................................. 21

20. Ovipositor sheath black or dark brown, contrasting in colour with apical metasomal segments; smaller species (fore wing 13–14 mm)............................................. O. sylvestris Johansson sp. nov.

– Ovipositor sheath testaceous, concolourous with apical metasomal segments; larger species (fore wing 15–17 mm)................................................................................... O. broadi Johansson sp. nov.

21. Usually a larger species (fore wing 15–17 mm); pterostigma evenly testaceous (Fig. 13D); wing membrane sometimes yellowish; male with malar space long (Fig. 21E); scutellum testaceous, concolourous with mesoscutum. Locally abundant in subalpine forest areas, very rare or absent in Central Sweden......................................................................................... O. kevoensis Jussila, 1965

– Usually a smaller species (fore wing 13–15 mm); pterostigma brownish, posteriorly and apically distinctly pale (Fig. 13B); male with malar space shorter (as in Fig. 21F); scutellum distinctly paler than mesoscutum. In heathlands of Southern Sweden.................. O. autumnalis Johansson sp. nov.

22. Temple buccate, behind eye in lateral view almost as wide as compound eye and usually with distinct gap between ocellus and eye (Fig. 30B)......................................................................................... 23

– Temple not buccate, behind eye in lateral view distinctly narrower than compound eye; ocellus touching or nearly touching compound eye (Fig. 15 A–B)............................................................. 25

23. Epicnemial carina, in antero-ventral view, with pleurosternal angles acute and almost level with sternal angles (Fig. 9F); mesopleuron densely punctate with distinct microsculpture; face below antennal sockets densely punctate (as in Fig. 8I); antenna with 59 or more flagellomeres.................................................................................................... O. angularis Johansson & Cederberg sp. nov.

– Epicnemial carina, in antero-ventral view, with pleurosternal angles slightly anterior to sternal angles (Fig. 9 A–B, G); pleurosternal angles obtuse, right angled or weakly acute; antenna frequently with fewer than 59 flagellomeres............................................................................................................ 24

24. Head slightly narrower in frontal view; clypeus wider; the distance between the upper end of the tentorial pits and compound eye about 0.5 times the distance between the pits (Fig. 14F); face with denser and larger punctures (as in Fig. 8I); mesopleuron usually slightly wrinkled, punctures larger; anterior transverse carina of propodeum strongly curved (Fig. 14D)... O. crassicornis Brock, 1982

– Head slightly wider in frontal view; clypeus more narrow; the distance between the upper end of the tentorial pits and compound eye equal to the distance between the pits (Fig. 14E); face with smaller and sparser punctures(as in Fig.8J); mesopleuron with smaller punctures and without any obvious wrinkles; anterior transverse carina of propodeum more straight (Fig. 14C).... O. borealis Johansson sp. nov.

25. Propodeum in females (less so in males) usually with carination complete, with anterior transverse carina distinct centrally and laterally; lateral longitudinal carinae usually distinct (Fig. 10C); surface between transverse carinae of propodeum often polished with irregular punctures; groove behind posterior ocellus deep and long, often diverging from the hind margin of ocellus (Fig. 15B); head of female in anterior and lateral view usually with compound eyes on average wide (Fig. 15D, G); occipital carina centrally evenly rounded (as in Fig. 7A); number of flagellomeres 59–64; nervellus broken distinctly below the middle (Fig. 13E)..................................... O. brocki Johansson sp. nov.

– Propodeum with dorsal carinae usually partly incomplete, anterior transverse carina always absent laterally, very rarely with lateral longitudinal carinae; surface between transverse carinae of propodeum often dull, shagreened; groove behind posterior ocellus shallower, following hind margin of ocellus (Fig. 15A); head in female in anterior and lateral view with compound eyes on average less wide (at most as in Fig. 15C, E); frequently with head strongly transverse and face much wider; number of flagellomeres usually fewer than 59; if number of flagellomeres is in the range of 59–62, then nervellus broken at or above the middle....................................................... 26

26. Larger species (fore wing 15–17 mm); epicnemial carina between tip of pleurosternal angles and sternal angles weakly concave, almost straight (Fig. 9A); pleurosternal angles obtuse; mesopleuron polished with very sparse and weak punctures; number of flagellomeres 59–63; nervellus broken at or above the middle (Fig. 13F). Mainly Southern Sweden.............. O. splendens Johansson sp. nov.

– Smaller species (fore wing 13–15 mm); epicnemial carina between tip of pleurosternal angles and sternal angles usually distinctly concave (Fig. 9B, G); pleurosternal angles acute or right-angled; mesopleuron frequently shagreened and with dense punctures; nervellus broken distinctly below the middle; number of flagellomeres fewer than 59. Two very similar species................................... 27

27. Occipital carina in most cases centrally evenly rounded, straight or with central depression (Fig. 7A), face below antennal sockets more often strongly shagreened with quite dense deep punctures (Fig. 8I); longitudinal carinae delimiting area superomedia often weak or missing anteriorly; area superomedia more often elongate; anterior transverse carina more often almost complete or indicated laterally; propodeum dorsally less shining with coarser structure; basal flagellomeres usually stouter, 1.4–1.5 times as long as wide (as in Fig. 8N)................................... O. confusus Johansson sp. nov.

– Occipital carina often centrally angled (Fig. 7B), sometimes with a small central arc; face below antennal sockets weakly shagreened or polished with scarce, shallower punctures (Fig. 8J); longitudinal carinae delimiting area superomedia often strong throughout their entire length; area superomedia more often as long as wide; anterior transverse carina usually absent laterally, only distinct adjacent to area superomedia; propodeum dorsally more shining; basal flagellomeres usually more elongate, 1.7–1.8 times as long as wide (as in Fig. 8O).................. O. mocsaryi Brauns, 1889

28. Sclerotised section of first sternite ending posterior to spiracle at a distance about three times the distance between the spiracle and the lower margin of the first tergite (Fig. 6F); propodeum and face polished with very deep and large punctures (Fig. 31B); pleurosternal angles very weakly defined (Fig. 9C); scutellum with lateral carinae along its entire length (Fig. 6D); malar space in male very wide, about 0.8 times as wide as mandibular base.A very rare species only known from two localities in the eastern part of Central Sweden............................................................ O. dispar Brauns, 1895

– Sclerotised section of first sternite ending posterior to spiracle at a distance at most equal to the distance between the spiracle and the lower margin of the first tergite (Fig. 6E)........................... 29

29. Mesopleuron and the entire propodeum infuscate (Figs 40, 45 A–B, 52A, E); first tergite usually with median dorsal undulation (as in Fig. 6E)........................................................................................ 30

– Mesosoma usually entirely testaceous, if infuscate areas are present they do not cover the above stated areas; first tergite with or without median dorsal undulation............................................... 31

30. Temple in lateral view about 0.8 times as long as compound eye (Fig. 19B); malar space long, about 0.4 times as long as mandibular base in female and about 0.4–0.5 times in male; head in anterior view with compound eyes narrow and face wide (Fig. 19A); hind coxa and mesosternum largely infuscate (Fig. 45 A–B)........................................................................ O. vardali Johansson sp. nov.

– Temple strongly narrowed behind eyes, about 0.3 times as long as compound eye (Figs 19F, 52 D–E), malar space short, about 0.1–0.2 times as long as mandibular base in female and about 0.2 times in male; ocellus large, lateral ocelli partly covering compound eye in dorsal view (Fig. 18 G–H); head in anterior view with compound eye wide and face narrow (Fig. 19E); hind coxa and mesosternum usually entirely testaceous (Figs 40, 52E)........................................ O. pteridis Kriechbaumer, 1879

31. Hind femur very slender, at least 8.0 times longer than wide (Fig. 16C); the longest spur of hind tibia distinctly shorter than 0.5 times as long as first hind tarsal segment (two early spring species)... 32

– Hind femur less slender, at most 7.0 times longer than wide (Fig. 16D); the longest spur of hind tibia about 0.5 times as long as first hind tarsal segment (species active during summer or autumn)... 33

32. Larger species (fore wing 15–19 mm); pterostigma narrow, about 3.5–4.0 times longer than wide; ramellus distinct (Fig. 16A); antenna with 60 or more flagellomeres, central flagellomeres about 2.0 times as long as wide; face narrower................................................... O. scutellaris Thomson, 1888

– Smaller species (fore wing 12–13 mm); pterostigma stouter, about 2.5–3.0 times longer than wide; ramellus short or absent (Fig. 16B); antenna with 55–60 flagellomeres, usually 56–57; central flagellomeres 1.5 times as long as wide; face wider..................... O. wuestneii Kriechbaumer, 1892

33. Subapical flagellomeres narrow and long, distinctly more than 2.0 times as long as wide (Fig. 8F); central flagellomeres about 2.0 times as long as wide; first tergite in lateral view with slight or distinct median undulation (Fig. 6E); pleurosternal angles distinctly anterior to sternal angles; pleurosternal angles obtuse (as in Fig. 9E); temple behind eyes quite narrow and lateral ocellus touching compound eye (Fig. 19 C–D)............................................ O. inclinans Johansson sp. nov.

– Subapical flagellomeres stout, at most 2.0 times as long as wide (Fig. 8 D–E); central flagellomeres about 1.3–1.5 times as long as wide; temple behind eyes narrow with ocellus touching compound eye or buccate with distinct gap between lateral ocellus and compound eye................................. 34

34. Head very strongly buccate, in lateral view head behind eyes at least as wide as compound eye (Fig. 20D); face in anterior view usually wide (Fig. 20C); female usually with posterior segments of metasoma often more or less infuscate (Fig. 35A); sclerotised section of first sternite ending level or slightly posterior to spiracle (Fig. 6 G–H); mandibles usually worn due to parasitising Cucullia -species pupating under ground. A rare species in semi-open areas in Southern Sweden................................................................................................. O. longigena Thomson, 1888

– Head less buccate or narrowed behind eyes, in lateral view usually narrower than compound eye; female with posterior segments of metasoma at most slightly infuscate ventrally; sclerotised section of first sternite ending slightly or distinctly posterior to spiracle (Fig. 6E, G); mandibles never worn................................................................................................................................................ 35

35. Smaller species (fore wing 12–14 (15) mm); antenna with 50 or fewer flagellomeres; central flagellomeres square (as in Fig. 8M); anterior transverse carina of propodeum absent or weak laterally; temple buccate in lateral view (Fig. 21D) and head with distinct gap between eye and lateral ocellus.................................................................................................................................. 36

– Larger species (fore wing 14–16 mm); central flagellomeres elongate, if rarely as long as wide, then antenna with 52 or more flagellomeres; anterior transverse carina of propodeum usually complete.......................................................................................................................................... 37

36. Face in anterior view with face wider in relation to compound eyes; head more rounded; malar space long, 0.4 times as wide as mandibular base in female and about 0.7 times in male (Fig. 17C, E); first tergite more elongate in lateral view, with median dorsal undulation (Fig. 20F); mesopleuron and metapleuron in Swedish specimens with distinct microsculpture between punctures; area superomedia more often elongate, about 1.3–1.5 times as long as wide. A rare species possibly connected to deciduous forests.................................................................... O. perkinsi Brock, 1982

– Face in anterior view with face narrower in relation to compound eyes; head more transverse; malar space short in both sexes, at most 0.2 times as wide as mandibular base (Fig. 17 D–F); first tergite stouter in lateral view, without dorsal median undulation (Fig. 20E); mesopleuron and metapleuron without distinct microsculpture between punctures; area superomedia more often as long as wide. A rare species mostly known from semi-open xerothermic habitats the southern provinces................................................................................................. O. norei Johansson sp. nov.

37. Temple strongly buccate, just slightly shorter than compound eye in lateral view (Fig. 20B): head with distinct gap between eye and lateral ocellus; propodeum distinctly punctate between the transverse carinae; first tergite often with more or less distinct dorsal undulation (as in Fig. 6E); antenna with 50–53 flagellomeres............................................... O. paukkuneni Johansson sp. nov.

– Temple more narrowed behind eye, distinctly shorter than compound eye in lateral view: head rarely with gap between lateral ocellus and compound eye; antenna usually with more than 54 flagellomeres................................................................................................................................... 38

38. Ramellus usually entirely absent (as in Fig. 16B), sometimes indicated by a small denticle; mesopleuron centrally distinctly depressed, the depression centrally with irregular wrinkles (Fig. 24B); sclerotised section of first sternite ending slightly posterior to spiracle, the distance at most equal to 0.5 times the distance between spiracle and ventral margin of first sternite, usually shorter (Fig. 6G); face below antennal sockets with dense punctures without interstices; antenna with 55–59 flagellomeres; nervellus broken distinctly above the middle. Rare, only known from Gotland (the Baltic Sea), Skåne and Blekinge (older records) and Kosteröarna (islands on the west coast of Sweden), probably slightly more common on Gotland................ O. artemisiae Boie, 1855

– Ramellus distinct, reaching at least 0.2 times the width of the discosubmarginal cell; mesopleuron centrally only slightly depressed, the structure of the depression centrally without irregular wrinkles; sclerotised section of first sternite ending distinctly posterior to spiracle, the distance equal to the distance between spiracle and ventral margin of first sternite (as in Fig. 6E); antenna with 50–56 flagellomeres; nervellus broken slightly above or below the middle............................................. 39

39. Pleurosternal angles right-angled or obtuse, distinctly anterior to sternal angles (as in Fig. 9E); subapical flagellomeres more elongate, about 1.8–1.9 times as long as wide (Fig. 8E); scutellum narrow; carination of propodeum indistinct with anterior transverse carina weaker laterally and central longitudinal carinae delimiting area superomedia weak or absent (some specimens of O. kevoensis might run out here, for separation of species see diagnosis)........... O. arenarius Johansson sp. nov.

– Epicnemial carina, in antero-ventral view, with pleurosternal angles slightly anterior to sternal angles (in females, less so in males); pleurosternal angles acute or right-angled, rarely obtuse (as in Fig. 9G); subapical flagellomeres stouter, about 1.5 times as long as wide (as in Fig. 8D); scutellum wider; carination of propodeum with anterior transverse carina raised laterally and longitudinal carinae delimiting area superomedia distinct................................................................................. 40

40. Mesoscutum more shining with more irregular and weak punctures; interstices between punctures about equal to their diameter or more (Fig. 21A); anterior and posterior transverse carinae of propodeum closer, thereby making the shape of the area superomedia about as long as wide (Figs 10G, 18F); second and third flagellomere more elongate, about 2.2 times as long as wide; nervellus usually broken slightly below the middle. A parasitoid of Hadena in open xerothermic grasslands, mostly in Eastern Sweden................................................. O. ellenae Johansson sp. nov.

– Mesoscutum less shiny with very dense and distinct punctures; interstices distinctly smaller than the diameter of punctures or absent (Fig. 21B); anterior and posterior transverse carinae of propodeum more separated, thereby making the shape of the area superomedia about two times as long as wide (Fig. 18E); second and third flagellomeres stouter, about 1.8 times as long as wide; nervellus broken slightly above the middle. Possibly a rare parasitoid of Hadena caesia (Denis & Shiffermüller, 1775) in coastal localities along the West coast of Sweden.............................. O. matti Johansson sp. nov.