An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species

Abstract The Chrysididae are a group of cleptoparasitic and parasitoid aculeate wasps with a large number of rare and endangered species. The taxonomy of this group has long been confusing due to the similarity of species and extensive intraspecific variation. We present for the first time a comprehensive dichotomous key for all 74 species found in the Nordic and Baltic countries. In addition to diagnostic characters, information on the distribution and biology of each species is also presented. A new species, Chrysis borealis Paukkunen, Ødegaard & Soon, sp. n. is described on the basis of specimens collected from Fennoscandia. Chrysis gracillima Förster, 1853 is recorded as new to the Nordic and Baltic countries.


Introduction
Chrysidid wasps, also known as cuckoo wasps, represent one of the largest families of aculeate Hymenoptera within the superfamily Chrysidoidea. More than 2.500 species are known worldwide (Aguiar et al. 2013) and approximately 490 of these have been recorded from Europe (Mitroiu et al. 2015). The species richness decreases towards the north of Europe, and a total of 74 species have been found in Fennoscandia, Denmark and the Baltic countries ). Cuckoo wasps, excluding Amiseginae and Loboscelidiinae, which are not present in Europe, are well known for their bright metallic colours and cleptoparasitic or parasitoid lifestyle. In northern Europe, species of the subfamily Chrysidinae parasitise solitary wasps (Vespidae and Crabronidae) and solitary bees (Megachilidae), whereas species of Cleptinae attack tenthredinid and diprionid sawflies. Despite their attractive appearance, chrysidids have a reputation for being a taxonomically difficult group, and the biology of several species is still poorly known.
A detailed history of cuckoo wasp research in the Nordic and Baltic countries was presented recently by Paukkunen et al. (2014). More than 200 publications including information on chrysidids have been published from the region, but most of them consist of only scattered records in poorly circulated journals or reports. Only a few authors have conducted more extensive faunistic studies at a national or wider scale. Faunistic surveys, including identification keys, have been compiled by Dahlbom (1829Dahlbom ( , 1831, Thomson (1862Thomson ( , 1870 and Aurivillius (1911) in Sweden, by Borries (1891) in Denmark, and by Sahlberg (1910) and Hellén (1920) in Finland. The monographs of Dahlbom (1845Dahlbom ( , 1854 also include keys and descriptions of several Nordic species. A simple key to the Swedish genera was later presented by Landin (1971). The faunistic studies from Estonia (Soon 2004), Latvia (Tumšs and Maršakovs 1970) and Lithuania (Orlovskytė et al. 2010) did not include identification keys of chrysidids. In recent decades, species determination of chrysidids in the Nordic and Baltic countries has mainly relied on the works of Linsenmaier (1951, Morgan (1984), Kunz (1994) and van der Smissen (2010), which focus primarily on the central European fauna, but include most of the North European species.
Scattered notes on the biology of European cuckoo wasps have been published by several authors in numerous articles and reports, and these data have been compiled by e.g. Kunz (1994) and . An important contribution to the knowledge of hosts of North European species was recently made by Pärn et al. (2014) in Estonia. The Nordic open access databases of entomological observations, Artportalen (http:// www.artportalen.se) in Sweden, Artskart (http://artskart.artsdatabanken.no) in Norway and Hyönteistietokanta (http://hyonteiset.luomus.fi) in Finland provide extensive sources of information on the phenology and habitats of cuckoo wasps. Many unpublished records of hosts, habitats and phenology can also be found in public and private cuckoo wasp collections.
As most publications with information on the identification and biology of the Nordic and Baltic cuckoo wasps are scattered, outdated and/or difficult to find or use, there is a need for a new comprehensive key for the North European species including biological information. Cuckoo wasps include an exceptionally large number of red-listed and endangered species in the Nordic countries, which also highlights the importance of their reliable identification , Hansen et al. 2010, Paukkunen 2010.
The aim of this study is to present a simple dichotomous identification key for the Nordic and Baltic species, and to compile all relevant and reliable information on their distribution, abundance and biology, including phenology and host species from publications and collections. The key will hopefully arouse more interest in chrysidids among entomologists, and provide a basis for further, more detailed studies on the distribution, biology and morphology of North European species.

Material and methods
The geographic area covered by the study includes the Nordic and Baltic countries, which are located in northern Europe (Fig. 1). The nomenclature and arrangement of the taxa follows Paukkunen et al. (2014) and , and the morphological terminology is based on Morgan (1984) and Kimsey and Bohart (1991), with a few exceptions. Most notably, mesosoma is used instead of thorax, metasoma instead of abdomen or gaster, mesoscutum instead of scutum and mesoscutellum instead of scutellum. These exceptions are made in order to harmonise modern general Hymenoptera terminology (Hymenoptera Anatomy Consortium 2015). The following abbreviations are used: T = tergite, S = sternite and F = flagellomere (= flagellar segment, pseudosegment of flagellum). Numbers are used for antennal and metasomal segments, for example, F2 refers to the second flagellomere. The key is mainly based on the works of  and van der Smissen (2010). In order to keep the key simple and concise, only easily visible and relatively constant characters have been selected. Several new diagnostic characters have also been found and included in the key. In addition to figures of morphological details, one dorsal habitus picture of an entire specimen is presented for each genus.
The species treatments consist of the following information: name, synonymy, diagnosis, distribution and biology. Only the more common synonyms and erroneously interpreted names, which have been used in connection with cited records from the study area, are presented below the valid name of the taxon. If the currently used name differs from the original combination, it is added to the synonymic list with a citation of the study, in which the rearrangement was made. The abundance of each species is estimated using the scale 1) very common (more than 5000 records), 2) common (ca 1000-5000 records), 3) relatively common (ca 500-1000 records), 4) relatively rare (ca 200-500 records), 5) rare (ca 10-200 records), 6) very rare (less than 10 records). This estimation is mainly based on collected material and therefore it essentially shows how commonly a species is collected, but might not accurately indicate its actual abundance in nature. A summary of the distribution of chrysidid species in the Nordic and Baltic countries is presented in Table 3.
The biology section includes information on the habitat, flight season and host species. The presented information on the distribution, abundance and biology has been compiled from published literature, entomological databases and several public and private collections, as well as our own observations. Host species, plants and habitats that are not found in the Nordic and Baltic countries are usually not mentioned. The most important studied collections are listed below:  Lists of examined material have not been included in the species treatments due to the large number of studied specimens. Accurate data is given only if a species is recorded for the first time from a country. Some information about the examined material has been published earlier by Paukkunen et al. (2014), and most of the Finnish data is openly accessible through the Finnish Biodiversity Info Facility (http://laji.fi). Data on DNA barcoded specimens are available at the Barcode of Life Data System (http://www.boldsystems.org, Ratnasingham and Hebert 2007).
Morphological measurements were prepared using an ocular micrometer on a Wild M5 and a Leica MZ75 stereomicroscope. All pictures were prepared by Alexander Berg, if not otherwise specified. The photos were taken with a Canon6D camera, using a Schneider-Kreuznach Componon-S 50 mm f2.8 and Schneider-Kreuznach Componon 28 mm f1.4 enlarger lenses extended on Pentacon M42 bellows. A Proxxon KT-70 microstage was used for photo stepping and Zerene Stacker v1.04 for stacking the photos.
In order to use the key successfully, specimens should be properly mounted or pinned with both the dorsal and ventral surfaces of the metasoma visible. In the Chrysis ignita and C. fasciata species-groups, the mandibles of both sexes should be opened, genital capsules of males should be extracted and ovipositors of females everted. Colouration of specimens collected with traps containing liquid preservatives, softened using hot water or having been kept in sunlight for a long time, can deviate from the original colouration. Additionally, the colour of fresh and liquid preserved specimens can change when they are dried, most notably greenish shades turn bluish in dry specimens. Geographical variation in colouration is also observed in many species, whereby northern specimens tend to be darker than southern ones.

Note.
Cleptes females search for tenthredinid and diprionid sawfly cocoons either on the host's foodplant or on the ground beneath and lay one egg per cocoon (Morgan 1984). The emerging larva develops as an ectoparasitoid of the sawfly prepupa within the cocoon (Darling and Smith 1985, Kimsey andBohart 1991). The genus consists of around 100 known species, the majority of which occur in the Holarctic Region (Kimsey and Bohart 1991, Wei et al. 2013, Arens 2014. A total of 27 species are known from Europe Soon 2012, Arens 2014) and three from the Nordic and Baltic countries . We have divided the genus into species-groups according to Móczár (1997Móczár ( , 2001.

Diagnosis.
Length 5-7 mm. Both sexes differ from C. semiauratus by not having a foveate furrow posteriorly on the pronotum (Fig. 13). The female also differs from C. semiauratus by its black head and mesoscutum, non-metallic yellow or orange pronotum, mostly metallic blue mesoscutellum, metanotum and propodeum, and non-metallic black apex of the metasoma. As opposed to the female, the head and mesosoma of the male are entirely metallic green and the apex of the metasoma has faint metallic reflections laterally (Fig. 16). Both sexes differ from C. semicyaneus by having pale brown or yellow (not dark brown) legs, denser punctation on the tergites (Fig. 16) and deep postocellar foveae on the vertex (Fig. 14). Distribution. Denmark, Estonia, Finland, Latvia, Sweden. Rare. -West Palearctic: Europe and Turkey , records from China are erroneous ).

Diagnosis.
Length 4-7 mm. Both sexes resemble C. nitidulus superficially, but the legs are darker brown, the punctation of the tergites is sparser (Fig. 17) and the vertex does not have postocellar foveae (Fig. 15). The female differs also from C. nitidulus by having blue-violet metallic sheen posteriorly on the metasoma. In the male, this blueviolet sheen is more extensive (Fig. 17) Bohart 1991, Carpenter 1999.

Tribe Elampini
Chrysidid wasps of this tribe are characterised by three external metasomal tergites, the absence of a pit row or sublateral foveae on T3, and the usually dentate tarsal claw. The tribe has a worldwide distribution, though most of the genera and species occur in arid areas of the Holarctic Region. A total of 21 genera are recognised, seven of which are found in North Europe.

Note.
Many authors have treated this genus in the broad sense and divide it into several subgenera (see summary by . We follow the classification of Kimsey and Bohart (1991), whereby Elampus, Philoctetes and Pseudomalus are recognised as valid genera. Omalus sensu stricto is characterised by the following morphological features: pronotum and mesoscutum without or with small punctures which are arranged evenly over the entire surface; mesopleuron projecting ventrally weakly, its lateroventral margin forming an obtuse angle in lateral view (Fig. 19); genal carina bisecting malar space. The larvae develop as parasitoids of crabronid wasps of the subfamily Pemphredoninae. Currently, 26 species are recognised worldwide, most of which are found in the Holarctic Region Bohart 1991, Wei et al. 2014). A total of eight species are found in Europe (Rosa and Soon 2012), and three are known from the Nordic and Baltic countries ). The status of several European taxa is uncertain, and the genus is in need of taxonomic revision.

Diagnosis.
Length 3-6 mm. The species resembles closely O. puncticollis, but usually has only very small punctures and short pubescence on the mesoscutum (Figs 18,22), sparser and finer punctation on the pronotum (Figs 18,22), and a shallower apical notch on T3 (Fig. 23). Some specimens have relatively coarse punctation medially on the pronotum and mesoscutum, but compared to O. puncticollis their pubescence is shorter, flagellomeres are longer, and the apical notch of T3 is shallower. In the female, the body is completely deep blue, violet or green (Fig. 18), whereas in the male it is dorsally black and laterally with green or blue reflections.
Remarks. Mitochondrial DNA studies indicate that the Nordic and Baltic specimens of O. aeneus belong to at least five genetically distinct lineages (excl. O. puncticollis), and several other lineages have been found in other countries . It is very likely that more than one species is involved. (

Diagnosis.
Length 3-6 mm. The species is easily confused with O. aeneus, but the mesoscutum always has relatively large scattered punctures and long setae (Fig. 24). The pronotum has also larger punctures medially ( Fig. 24) and the apical notch of T3 is deeper (Fig. 25). The body colouration is similar to O. aeneus. Habitus of large specimens can sometimes resemble small specimens of Pseudomalus violaceus, but the ventral margin of the mesopleuron is not as strongly projecting in O. puncticollis (as in Fig. 19) and the large punctures of the mesoscutum are not clumped postero-medially.
Distribution. Norway, Sweden. Rare. -West Palearctic (?): Europe, Turkey and northern Africa (Linsenmaier , 1968(Linsenmaier , 1999. The general distribution is poorly known, because many authors have considered O. puncticollis to be conspecific with O. aeneus. Biology. Habitat: forest margins and clearings, semi-open sandy areas. Adults are usually found sitting on or flying near leaves of trees and bushes, occasionally also on flowers of Apiaceae (Kunz 1994). Flight period: June to August. Host: Passaloecus gracilis (Curtis), P. eremita Kohl, P. corniger Shuckard and P. turionum Dahlbom (Crabronidae) (Spooner 1954, Gauss 1967, Mocsáry 1912 Note. This taxon was raised to generic rank by Kimsey and Bohart (1991). It is characterised by the structure and punctation of the mesosoma: the large punctures are clumped posteriorly between the notauli on the mesoscutum (Fig. 27), and the lateroventral margin of the mesopleuron is strongly projecting ventrally, forming a sharp angle in lateral view (Fig. 28). The posterior margin of T3 is usually deeply notched medially (Figs 31,32). Pseudomalus is a Holarctic genus with approximately 40 recognised species (Kimsey and Bohart 1991). The larvae are parasitoids of crabronid wasps of the subfamily Pemphredoninae. The European fauna consists of ten species (Rosa and Soon 2012), of which four have been found in the Nordic and Baltic countries ).

Diagnosis.
Length 3-5 mm. The species differs from other Pseudomalus species by having an entirely green, green-golden or green-blue body with usually golden reflections on the mesoscutum, mesoscutellum and metanotum. Dark specimens can be confused with unusually dark specimens of P. auratus, but the apex of the metasoma protrudes more narrowly, the metascutellum is more elevated medially ( Fig. 29) and the pubescence is shorter. Distribution. Denmark, Latvia and Lithuania. Very rare. -Trans-Palearctic: from western Europe and northern Africa to Russian Far East (Kurzenko and Lelej 2007).

Diagnosis.
Length 3-6 mm. Both sexes have a bicoloured body with a blue-green or violet head and mesosoma, and a red (or rarely entirely greenish) metasoma with green reflections (Fig. 26). The species is very similar to P. triangulifer, but the antennal segments are shorter ( Fig. 33) and the body is usually smaller. The apical notch of T3 is also deeper and more rounded dorsally (Fig. 32).

Distribution.
Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Common. -Trans-Palearctic/Holarctic: from western Europe and northern Africa to China, Korea and Japan. Introduced accidentally to North America (Kimsey and Bohart 1991).

Diagnosis.
Length 6-7 mm. The species resembles closely P. auratus, but the antennal segments are longer ( Fig. 34), the body is usually larger and the shape of the apical notch of T3 is shallower and more triangular (Fig. 31). The colour of the metasoma varies from mostly red to almost green. The darkest specimens can be somewhat similar to P. violaceus, but the apical notch is always deeper in P. triangulifer.

Diagnosis.
Length 5-8 mm. The species differs from other species of the genus by its completely violet-blue (female) or black-green to black-blue (male) body, and a wide and shallow apical notch on T3. The scapal basin is also higher and dorsally deeply angled. Exceptionally small and worn specimens can be confused with Omalus puncticollis (or O. aeneus), but the mesopleuron of P. violaceus always strongly projects ventrally (as in Fig. 28) and the mesoscutum has large punctures, which are clumped postero-medially (as in Fig. 27).

Note.
The taxonomic rank and delineation of Philoctetes has differed among several authors. We follow the definition given by Kimsey and Bohart (1991) and consider it as a distinct genus. Philoctetes is characterised by the following diagnostic features: mesoscutum with large punctures concentrated along notauli; central malar space without carina; mesopleuron rounded and weakly projecting ventrally; metascutellum usually conical; posterior margin of T3 usually deeply notched me- Approximately 40 species are recognised worldwide, and about 30 of these are Palearctic (Kimsey and Bohart 1991). A total of 22 species are known from Europe (Rosa and Soon 2012), but only P. truncatus is found in the Nordic and Baltic countries

Diagnosis.
Length 3-5 mm. The species resembles Omalus aeneus and O. puncticollis by its habitus and colouration. In the female, the body is completely shiny deep blue, violet or green ( Fig. 35), whereas it is mainly black with green or blue reflections in the male. Compared to Omalus species, the metascutellum is more sharply elevated and the punctures on the mesoscutum are larger. The apical notch of T3 is shallowly triangular and bordered by a thickened margin (Fig. 36). The lateral margins of T3 are semitransparent and strongly convex adjacent to the apical notch ( Fig. 36).
Biology. Habitat: sparsely vegetated sandy areas, sandstone and loess banks (Heinrich 1964, our own obs.). Adults occasionally visit flowers of Apiaceae (Trautmann 1927. Flight period: June to July. Host: Diodontus tristis (Vander Linden) (Crabronidae) (Hoop 1961, Saure 1998, Jacobs and Kornmilch 2007, our own obs.). Note. This genus has been treated as a subgenus of Omalus by some authors (e.g. . It is well characterised by the shape of the metascutellum, which has a large tongue-like projection dorsally (Fig. 38). The posterior margin of T3 is usually extended into a horseshoe-shaped or falcate rim forming truncation (44)(45)(46). The female has a row of dense and erect setae along the genal margin (Fig. 41). These setae are replaced by long irregularly placed bristles in the male. The hosts are ground-nesting crabronid wasps, such as Mimesa Shuckard and Mimumesa Malloch (Kimsey and Bohart 1991). The genus is distributed in the Palearctic Region (more than 40 species), North America (8 species), Africa (7 species) and South America (3 species) (Kimsey and Bohart 1991, Linsenmaier 1999, Madl and Rosa 2012. A total of 12 species have been found in Europe (Rosa and Soon 2012), and three of these occur in the Nordic and Baltic countries ).

Diagnosis.
Length 4-7 mm. The species differs from E. panzeri and E. foveatus by the structure of the apical truncation of T3, which has pointed margins ventrally and resem-bles a sickle or a boomerang in shape (Fig. 45). Sometimes the apical truncation is very narrow, similar to that of Philoctetes truncatus. The lateral margins of T3 are shallowly concave anterior to the apical truncation. As opposed to E. panzeri and E. foveatus, the scrobal carina reaches the angle of the omaulus (Fig. 42). Both sexes are usually bicoloured with a blue or greenish head and mesosoma, and a reddish metasoma. Entirely greenish or blue specimens are found occasionally. Distribution. Denmark, Estonia, Finland, Norway, Sweden. Relatively rare. -Trans-Palearctic: widely distributed in the Palearctic Region, from Europe to China ).

Diagnosis.
Length 5-8 mm. The species can be confused with E. constrictus and E. panzeri, but the apical truncation of T3 has rounded margins ventrally and resembles a thick, upside-down U in shape (Fig. 46). The lateral margins of T3 are similar to E. constrictus (Fig. 40). The punctation of T2 is somewhat more irregular than in E. constrictus, and usually an impunctate medial line is formed anteriorly. The scrobal carina ends below the angle of the omaulus (Fig. 43) as in E. panzeri. The head and mesosoma are blue or greenish, and the metasoma is red with green reflections in both sexes.
Distribution. Estonia, Finland, Norway, Sweden. Rare. -Trans-Palearctic: from the Netherlands to Siberia (Usolye-Sibirskoye). The distribution is still poorly known, because many authors have confused E. foveatus with other closely related taxa.
Biology. Habitat: sparsely vegetated sandy areas. In Germany, specimens have been found on Sambucus bushes (Niehuis and Gauss 1996

Diagnosis.
Length 4-8 mm. The species resembles E. constrictus and E. foveatus, but the apical truncation of T3 has angular margins ventrally and resembles a horseshoe in shape (Fig. 44). The lateral margins of T3 also have narrow notches in front of the apical truncation (Fig. 39). The punctation of T2 is somewhat sparser than in E. constrictus and E. foveatus. The scrobal carina is similar to E. foveatus (Fig. 43). Both sexes are bicoloured with a green or blue head and mesosoma, and a red metasoma with green reflections (Fig. 37). Rarely the metasoma can be entirely greenish.

Diagnosis.
Length 4-7 mm. The female and the male are entirely differently coloured. The female is mainly shiny red-purple, but the legs, mesopleuron, metanotum, propodeum, lower part of head and lateral corners of pronotum are blue. The male is entirely green or blue-green, sometimes with golden reflections or a completely golden metasoma. The colouration of the male is similar to H. metallica, but the punctation of the tergites is denser and coarser ( Fig. 49) and the antennal segments are shorter (Fig. 51). Distribution. Denmark. Very rare. Only two records are known from the island of Lolland (1 ♀, Bremersvold, 20. VII.1904, and 1 ♀, Røgebølle, 5. VII.1912, both leg. L. Jørgensen). -West Palearctic: Europe, northern Africa, Turkey, Iran Bohart 1991, Rosa et al. 2013).

Diagnosis.
Length 5-6 mm. The female is entirely blue or blue-green with golden green reflections on the pronotum, mesoscutum and metasoma. The male is golden green with blue on the metanotum and propodeum. Both sexes resemble the male of H. fervida in colouration, but the punctation of the tergites is finer and sparser ( Fig. 50), and the antennal segments are longer in the male (Fig. 52

Diagnosis.
Length 7-9 mm. Both sexes are similarly bicoloured with a green or blue head and mesosoma, and a dorsally red metasoma (Fig. 47). The colouration resembles that of Hedychrum gerstaeckeri and the male of H. nobile and H. niemelai, but H. generosa always has multidentate tarsal claws (Fig. 3), angular margins on the head (as in Fig. 48) and an evenly rounded margin of T3 (as in Figs 49, 50). In Hedychrum, the claws are bifid, the head margins are rounded and T3 usually has angular prominences laterally.
Host: Astata boops (Schranck) (Crabronidae) (Veenendaal 2012, our own obs.). Females lay their eggs in nymphs of Heteroptera before they have been captured and brought to the nest by the host (Veenendaal 2012).

Diagnosis.
Length 5-7 mm. Both sexes have similar colouration: the head, propleuron, mesopleuron, propodeum and legs are blue or blue-violet, whereas the pronotum, mesoscutum, mesoscutellum and metascutellum are red. The colouration is relatively similar to the female of H. fervida, but the head is completely blue (without red vertex), the metascutellum is red (not blue) and the mesoscutellum is uniformly punctured (not sparser anteriorly).
Distribution. Finland, Lithuania. Very rare. In Finland, more than 30 specimens were collected in the south-eastern part of the country (Joutseno) in 1957-1960, but currently the species is classified as regionally extinct (Paukkunen 2010). In Lithuania, no records are known since 1970 (Orlovskytė et al. 2010). -West Palearctic: Europe, northern Africa, western Asia (Linsenmaier , 1999.

Diagnosis.
Length 4-10 mm. The species is usually easy to differentiate from other Hedychrum species by the coppery red colour on the head dorsum, pronotum, mesoscutum and mesoscutellum. Also the pubescence is paler brown than in other species. The ventral part of the head, metanotum, propodeum, mesopleuron and legs are contrastingly blue or blue-green. Sometimes the coppery red colour of the head and/or mesosoma is partially replaced by golden green or blue colour, especially in the male. The mesotibia of the male has a shallow depression on its inner surface, reaching half of the tibial length. The female does not have an apicomedial tubercle on S3.

Diagnosis.
Length 6-10 mm. The male and female are differently coloured. In the male, the head and mesosoma are completely green-blue and the metasoma is golden red (rarely greenish golden). In the female, the pronotum and mesoscutum are bright red (as in Fig. 53) or golden yellow, whereas the rest of the body has similar colouration as in the male. The pubescence is dark brown in both sexes. The species is easily confused with H. niemelai, but the mesotibial groove of the male is shallower and narrower, often indistinct ( Fig. 57), and the female has a broader, apically undivided, tubercle on S3 (Fig. 59). Punctation of T3 is also sparser in both sexes, especially in the male (Fig. 62).

Diagnosis.
Length 5-8 mm. The colouration is similar to H. nobile, but the pronotum and mesoscutum of the female are usually bright red ( Fig. 53) and rarely yellowish. The mesotibial depression of the male is deeper than in H. nobile and oval or longitudinal in shape (Fig. 58). The tubercle on the posterior margin of S3 of the female is apically divided and smaller ( Fig. 60) than in H. nobile. Additionally, the punctation of T3 is denser, especially in the male (Fig. 63).

Diagnosis.
Length 4-6 mm. The male is easy to differentiate from other Hedychrum species by its entirely green-blue body. Therefore it superficially resembles Holopyga metallica and the male of H. fervida. The female is completely differently coloured: the vertex, pronotum, mesoscutum, mesoscutellum and dorsum of the metasoma are bright red, whereas the ventral and lateral parts of the head and mesosoma, including the legs, are blue or greenish. The pubescence is dark brown and the apicomedial tubercle on S3 of the female is very small. Distribution. Latvia, Lithuania. Very rare. The species has been recorded in one locality in Latvia (Tumšs 1976) and in three localities in Lithuania (Wengris 1962).
-Trans-Palearctic: from western Europe to Russian Far East, Mongolia and China ).

Diagnosis.
Length 3-5 mm. The species is characterised by the very dense and fine punctation of the pronotum and mesoscutum, whereby the surface appears completely dull (Fig. 68). The mesoscutellum also has dense punctation and rugae between the punctures (Fig. 68). In H. ardens, H. cupreum and H. purpurascens the punctation is sparser and the surface shinier. The colour of the vertex, pronotum, mesoscutum and mesoscutellum is brownish red (Fig. 68). The frons, anterior corners of pronotum, metanotum, propodeum, mesopleuron and tibiae are mainly green or blue. The metasoma is coppery red or sometimes greenish.

Diagnosis.
Length 4-5 mm. The species differs from other species of the genus by having very sparse punctation and smooth interstices between punctures on the mesoscutum and mesoscutellum (Fig. 69). The head and mesosoma are dorsally mainly coppery red or greenish (Fig. 69), whereas the metasoma is dorsally red-purple with blue-green reflections. The frons, anterior corners of pronotum, metanotum, propodeum, mesopleuron and tibiae are mainly green or blue. Compared to H. purpurascens, the metasomal pubescence is longer (Fig. 71) and the scapal basin has broader crossridging. S2 does not have a clearly delimited metallic spot medially.

Diagnosis.
Length 5-6 mm. The species closely resembles H. cupreum, but the colouration of the head and mesosoma are dorsally darker violet (Fig. 70), sometimes nearly black. The punctation of the mesoscutum and mesoscutellum is denser (Fig.  70), the pubescence of the metasoma shorter (Fig. 72) and the fine cross-ridging of the scapal basin is restricted to a smaller area medially. S2 has a round metallic spot medially (Fig. 73).
Distribution. Estonia. Very rare. Nine specimens were collected in 2013 from Kauksi, northern shore of Lake Peipus. No other records are known from the Nordic and Baltic countries. -West Palearctic: central Europe .
Biology. Habitat: sparsely vegetated sandy areas. Adults often sit on roots of trees and bask in the sun (Trautmann 1927

Diagnosis.
Length 5-7 mm. Together with H. roseum this species is easily differentiated from other species of the genus by its non-metallic red or orange metasoma. The head and mesosoma are mainly green or blue, but as opposed to H. roseum, the vertex, pronotum and lateral fields of the mesoscutum have coppery red colour or reflections. This coppery colour is sometimes only weakly visible. The metasoma often has weak purple reflections posteriorly. Especially in the males, the punctation of T3 and T2 is usually coarser compared to H. roseum , Kurzenko and Lelej 2007).

Tribe Chrysidini
Members of this tribe are characterised by the simple untoothed tarsal claw, the transverse subapical pit row on T3, and the transverse preoccipital welt or carina (Kimsey and Bohart 1991). With more than 1.500 species and 30 genera, Chrysidini is the largest tribe of Chrysididae. A total of 11 genera are known from Europe (Rosa and Soon 2012), five of which are found in the Nordic and Baltic countries  Note. This taxon has been treated as a subgenus of Euchroeus Latreille or Spinolia Dahlbom by some authors , Morgan 1984, Arens 2014. We follow the classification of Kimsey and Bohart (1991) and regard it as a distinct genus. Character-  (Kimsey and Bohart 1991). The European fauna consists of eight species (Rosa and Soon 2012), and one, P. neglecta, is found in the Nordic and Baltic countries

Diagnosis.
Length 5-9 mm. Both sexes are bicoloured with a green or blue head and mesosoma, and a golden red metasoma (Fig. 75). The vertex and the anterior margin of the pronotum often have golden reflections. The metasoma is very finely and densely punc-tured on the tergites, causing the surface to appear dull (Fig. 75). The posterior margin of T3 is edentate. The species can be confused with similarly coloured species of Chrysura, but the radial sector vein of the forewing does not reach the wing margin (Fig. 10).

Diagnosis.
Length 4-6 mm. The species is characterised by the entirely blue, greenish or violet-blue body, and the forewing radial sector vein, which ends remote from the wing margin (Fig. 76). The T3 is posteriorly edentate and has a small tooth anteriorly. Biology. Habitat: xerothermic sparsely vegetated sandy areas, often close to the seashore. Adults occasionally visit flowers of Asteraceae, Lamiaceae and Rosaceae (Trautmann 1927, Benno 1950 several variable and non-unique characters, such as the closed or nearly closed forewing marginal cell, the usually four-or six-toothed posterior margin of T3, and the usually distinct transverse frontal carina on the frons. Members of the genus parasitise a wide range of solitary wasps and bees in the families Vespidae, Sphecidae, Crabronidae, Megachilidae and Apidae. They are found worldwide, but the vast majority of species is found in the Holarctic and Afrotropical Regions. The European fauna consists of nearly 190 species and numerous subspecies (Rosa and Soon 2012). Up to now, 35 species have been found in the Nordic and Baltic countries ). The genus was first formally divided into species-groups by . Our classification of the species-groups follows Kimsey and Bohart (1991).

Key to Chrysis species of the Nordic and Baltic countries
1 Posterior margin of T3 medially pointed or rounded without teeth (Fig. 77) .....
Punctation of mesoscutum finer, punctures not differing in colour from interstices .

Diagnosis.
Length 4-7 mm. The species is easy to recognise by the edentate posterior margin of T3 and the narrow, elongate body shape. Species of Chrysura, which are similarly coloured and also lack apical teeth, do not have the scapal basin or the dark apical rim, and are larger in size. The head and mesosoma are mainly blue or greenish with golden reflections, and the mesoscutum is medially contrastingly darker than laterally. The metasoma is completely golden red dorsally, but the apical rim is dark blue or blackish. The apical rim is wide, medially slightly undulating and laterally with angled margins. F2, F3 and F4 are ventrally slightly bulging in the male. The shape of the body is very slender and elongate in both sexes. Distribution. Estonia. Very rare. One female was collected on 14. VII.2015 in Reinu, southwestern Estonia (58.032°N, 24.747°E, leg. V. Soon). No other records are known from the Nordic and Baltic countries, but one female has been collected from Russia, close to the eastern border of Latvia (Pskov Oblast, Krasikovo, 23 km south of Sebezh, VII.1999, leg. A. Reschikov). -West Palearctic: Europe, northern Africa and Middle East .

Chrysis bicolor Lepeletier, 1806 Figs 110, 138
Chrysis bicolor Lepeletier, 1806: 127. Chrysis succincta var. virideocincta Trautmann, 1927: 160. Diagnosis. Length 5-8 mm. The species resembles C. illigeri, but the malar space is shorter (Fig. 138), the punctation of T2 is denser and the metascutellum is more raised in profile. Also the black spots of S2 are posteriorly more oblique in the female (Fig.  110). The head and mesosoma are mainly blue or greenish, but the mesoscutum and anterior margin of the pronotum are red or golden red in the female and golden green to greenish in the male. The mesoscutum is usually darkened medially in the male. The metasoma is mainly red in the female and golden greenish in the male with a greenish, bluish or black apical rim. T2 often has a black patch dorsally in the female.
Biology. Habitat: sparsely vegetated sandy areas. Adults occasionally visit flowers of Apiaceae, Asteraceae, Euphorbiaceae and Rosaceae , Rosa 2004, our own obs.). Flight period: early June to late August. Host: Tachysphex obscuripennis (Schenck) and T. pompiliformis (Panzer) (Crabronidae) (Morgan 1984, Saure 1998, Wickl 2001. In central and southern Europe also Dinetus pictus (Fabricius) (Crabronidae) (Gauss 1967). Trautmann, 1927 Fig. 171 Chrysis succincta var. westerlundi Trautmann, 1927: 159. Chrysis succincta var. nordströmi Trautmann, 1927: 159. Chrysis westerlundi: Linsenmaier 1959 Diagnosis. Length 7-9 mm. The species differs from other North European species of the C. succincta group by its characteristic colouration: the head and mesosoma are completely dark blue or almost black dorsally in the female and green blue in the male. The metasoma is dorsally red in both sexes and anteriorly greenish in the male. The metatarsus is long, the second tarsomere is at least 3.5 times as long as broad (Fig.  171). Superficially, the species can resemble similarly coloured species of the C. ignita group, but the two central apical teeth are close to each other and extend further posteriorly than the lateral teeth (as in Fig. 78). Also the black spots of S2 are large and not separated by a metallic central line.  Finland. Very rare, only eight specimens (6 females and 2 males) are known. -West Palearctic: the species has been found only from Finland and Russian Fennoscandia   var. chrysoprasina Trautmann, 1927: 159, not Förster, 1853. Chrysis succincta f. helléni Balthasar, 1953, replacement name for chrysoprasina Trautmann, 1927. Chrysis helleni Linsenmaier, 1959: 113, not Balthasar, 1953.

Diagnosis.
Length 5-8 mm. The species resembles C. bicolor in colouration, but the anterior margin of the pronotum, the mesoscutum and the metasoma are usually mainly red in the male (not greenish), and the posterior margins of the black spots of S2 are not as oblique in the female (Fig. 111). Compared to C. bicolor, the malar space is longer (Fig.  139), the punctation of T2 is sparser and the metascutellum is not as elevated in profile.

Diagnosis.
Length 4-8 mm. The species can be differentiated from other Nordic and Baltic species of the C. succincta group by having a rounded or slightly pointed, edentate posterior margin of T3 (Fig. 77) and a blue mesoscutellum. In C. leachii, the posterior margin of T3 is also edentate, but the mesoscutellum is mostly red. The scapal basin is largely shiny, without cross-ridging in the female, and mostly densely microsculptured in the male, with only a narrow central dull longitudinal line. The head, most of the mesosoma, base of T1 and the apical rim are green or blue, whereas the anterior margin of the pronotum and the mesoscutum are red in the female and golden green in the male. The metasoma is dorsally mainly red, or often greenish in the male.

Diagnosis.
Length 3-6 mm. The species is similar to C. succincta in having an edentate posterior margin of T3 (as in Fig. 77), but the margin is medially more sharply pointed, especially in the female. The center of the scapal basin is finely cross-ridged (Fig. 150) or it is dull and densely microsculptured. The colouration resembles that of C. succincta, but the mesoscutellum is red (not blue) and the tergites are often posteriorly narrowly green or blue. The males are usually more greenish than females.

Chrysis scutellaris Fabricius, 1794
Chrysis scutellaris Fabricius, 1794: 458. Chrysis segmentata Dahlbom, 1829: 9. Diagnosis. Length 6-9 mm. The species is easily recognised due to its unique colouration among North European chrysidids. The head and the mesosoma are mainly blue or green, but the meso-and metascutellum are red or golden. Usually also the frons, the anterior margin of the pronotum and the lateral sections of the mesoscutum have golden or coppery reflections. The metasoma is dorsally red, but the apical rim of T3 is contrastingly blue. The apical teeth are shallow and indistinct, whereby the apical rim may appear nearly rounded.
Distribution. Denmark, Lithuania, Sweden. Rare. Only a few records from Denmark and Sweden (Scania) and one record from Lithuania are known (Orlovskytė et al. 2010, Sörensson et al. 2012). -West Palearctic: Europe and northern Africa (Linsenmaier , 1999.
Remarks. Mitochondrial DNA sequences available at the Barcode of Life Data System (Ratnasingham and Hebert 2007) indicate that Swedish specimens of C. scutellaris differ genetically remarkably from central European specimens. The status of European populations should be studied more in the future.

Diagnosis.
Length 5-8 mm. The colouration is similar to C. rutilans, as the head, mesosoma and T3 are green, blue, or partially black, whereas T1 and T2 are golden red. Compared to C. rutilans, the body is more robust and the punctation of T2 is coarser (Fig. 95). T2 has a distinct polished longitudinal keel medially and its posterior margin is narrowly raised (Fig. 95). The black spots of S2 are shorter (Fig. 114) and the head is broader than in C. rutilans. Distribution. Latvia. Very rare. Only three records are known from eastern and central Latvia. -Trans-Palearctic: Europe, central Asia, Japan and Korea (Linsenmaier 1997, Kurzenko andLelej 2007).

Diagnosis.
Length 5-9 mm. The species resembles C. splendidula in colouration, but the body is more slender and the punctation of T2 is finer (Fig. 94). Also, T2 does not have a distinct smooth longitudinal keel or a raised posterior margin (Fig. 94). The black spots of S2 are longer and the head is narrower than in C. splendidula.
Remarks. The status of the closely related species C. insperata is still uncertain. It is difficult to separate from C. rutilans, and Kunz (1994) and several subsequent authors consider C. insperata as a nomen dubium. However, some authors (e.g. , Strumia 1995, 2005) considered both C. insperata and C. rutilans as valid species. Mitochondrial DNA sequences available at the Barcode of Life Data System (Ratnasingham and Hebert 2007) suggest that probably only one species is present in the Nordic countries.

Diagnosis.
Length 6-8 mm. The species resembles C. viridula by its colouration, but the head is dorsally partially red (not blue or green) in the female and occasionally also in the male. The mesosoma is dorsally red, as in C. viridula, but the mesoscutum is medially green or blue in the male. The setae medially on the metatibia are shorter than the width of the tibia (Fig. 165) (not longer, as in C. viridula). Denmark. Very rare. Only one female specimen is known from the island of Lolland (Strandby, 2. VIII.1919, leg. L. Jørgensen). -West Palearctic: southern Europe .

Diagnosis.
Length 6-9 mm. The species is easy to recognise due to its distinctive colouration: the head, lateral and ventral parts of the mesosoma (including legs) and T3 are green, blue or violet, whereas the dorsal parts of the mesosoma, most of T1 and the entire T2 are red. The setae medially on the metatibia are longer than the tibial width (shorter in C. pulcherrima). The apical teeth of T3 are often shallow and indistinct (Fig. 79).
Distribution. Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Common. -Trans-Palearctic: from western Europe to Russian Far East, Korea, China and Japan , Kurzenko and Lelej 2007 Adlerz 1910, Morgan 1984. The female oviposits in the host nest only when the host larva has completed its growth .

Diagnosis.
Length 7-9 mm. The colouration is unique among North European chrysidids. The head and mesosoma are blue or greenish, and the mesoscutum is medially often dark blue or nearly black. The metasoma is dorsally red, but the apical rim of T3 is contrastingly blue.

Diagnosis.
Length 6-9 mm. The body is entirely dark blue or violet with greenish reflections. Usually the male is more greenish or lighter blue than the female. The species can be confused with C. iris, but the mesoscutum is medially distinctly darker than laterally (Fig. 156), the punctation of the mesoscutum is denser and the ovipositor is broader (as in Fig. 91). Also the black spots of S2 are smaller and the apical teeth of T3 are more sharply produced (Fig. 82).
Distribution. Sweden. Very rare. Only one specimen is known from Östergötland, collected probably in the late 1840s or early 1850s (leg. A.G. Dahlbom). -West Palearctic: central and southern Europe, northern Africa, Asia Minor .
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood (Trautmann 1927, 1930, Heinrich 1964, Brechtel 1986. Adults occasionally visit flowers of Apiaceae (Trautmann 1927. Flight period: June to August. Host: possibly Gymnomerus laevipes (Shuckard) (Vespidae) and/ or Ectemnius rubicola (Dufour and Perris) (Crabronidae) (Dufour and Perris 1840). Diagnosis. Length 7-12 mm. The species differs from other North European chrysidids by its unique colouration. The head, mesosoma and T1 are dark blue or violet blue, whereas T2 and T3 are bright red (or rarely greenish) in the female. T1 often has golden reflections laterally. The male resembles the female in colouration, but T2 has a large dark blue or nearly black patch antero-dorsally with greenish margins (Fig. 93).

Diagnosis.
Length 7-13 mm. The body is mostly blue or blue-green, resembling C. indigotea in colouration. The female often has green-golden reflections on the mesoscutum, mesoscutellum and anteriorly on the pronotum. The tergites are posteriorly lighter blue than anteriorly. Compared to C. indigotea, the punctation of the mesoscutum is sparser and the interstices larger, the mesoscutum is medially not distinctly darker than laterally, and the ovipositor is narrower (as in Fig. 92). The black spots of S2 are also larger and the apical teeth of T3 shorter and blunter.

Diagnosis.
Length 7-10 mm. As in most other species of the C. ignita group, the head and mesosoma are mainly blue or green and the metasoma is dorsally golden red. However, the mesoscutum, mesoscutellum and propodeum, and often also tegulae and mesopleuron, have extensive golden or coppery reflections in the female. The sternites and legs are ventrally coppery red in both sexes. The punctation of the tergites is very fine and dense throughout, punctures being of uniform size (Fig. 96). In the male, the punctation is often somewhat sparser, and therefore it is more easily confused with other similarly coloured species of the C. ignita group (e.g. C. subcoriacea). The combination of a short pronotum (length less than one fourth of its width), non-metallic F1 and coppery red sternites should be used to distinguish C. ruddii males reliably from other species of the group.
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood. Rarely also sandy banks and clay structures, such as old barn walls. Flight period: early June to early August. Host: Symmorphus gracilis (Brullé) (Vespidae) (Pärn et al. 2014). Linsenmaier, 1951 Figs 98, 162 Chrysis ignita var. clarinicollis Linsenmaier, 1951: 77. Chrysis clarinicollis: Schmid-Egger et al. 1995 Diagnosis. Length 6-10 mm. The species is characterised by a uniformly green or bluegreen pronotum and mesoscutellum, and a contrastingly darker blue or violet mesoscutum (Fig. 162). The tergites are mainly golden red, but T1 is anteriorly and laterally blue-green or green (Fig. 98). Shape of the metasoma is broad and compact (Fig. 98). Punctation of T2 is somewhat finer than on T1 and dense throughout (Fig. 98). The sternites and legs are ventrally greenish. The apical rim of T3 is narrow and the intervals of the apical teeth very shallow (Fig. 98). The mandible and ovipositor are thin (as in Figs 92 and 141). Males in particular can be confused with other species of the C. ignita group as their colouration is more variable than in females. The colouration should always be used in combination with other characters (e.g. shape of metasoma and apical teeth) in species identification.
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood. Usually observed on dead tree trunks and on walls of abandoned houses , but also flying near the ground and over rocks . Flight period: June to August. The earliest Estonian specimens were collected in the beginning of June and the latest in the end of July. Host: possibly Ancistrocerus oviventris (Wesmael) and/or A. scoticus (Curtis) (Vespidae) (Petit 1987). Linsenmaier, 1959 Figs 97, 115, 140, 159 Chrysis rutiliventris ssp. vanlithi Linsenmaier, 1959: 153. Chrysis rutiliventris of authors, not Abeille de Perrin, 1879. Chrysis vanlithi: Soon et al. 2014: 305.

Diagnosis.
Length 7-10 mm. The species is easily confused with other similarly coloured species of the C. ignita group (e.g. C. borealis sp. n. and C. schencki), and the males in particular can be difficult to identify. The combination of several characters (e.g. shape of pronotum and malar space and colouration) should always be used in species determination. The head and mesosoma are dorsally dark blue or nearly black with light blue or greenish reflections mainly on the pronotum (Fig. 159). The tergites are golden red ( Fig. 97) and the sternites and legs ventrally greenish (Fig. 115). The pronotum is short (length not more than one fourth of width) (Fig. 159). The mandible is relatively thin (Fig. 140) and the malar space long, approximately as long as broad in the female (Fig. 140). F1 is black without a metallic sheen, and the ovipositor is narrow (as in Fig. 92).

Distribution.
Denmark, Norway, Sweden. Rare. Only one confirmed record is known from Denmark, four from southern Sweden (Scania, Bohuslän and Stockholm archipelago) and ten from southern Norway. -West Palearctic: from central and northern Europe to southwestern Asia .

Diagnosis.
Length 9-13 mm. Females are usually easy to recognise by the laterally coriaceous and dull T2 and T3 (Fig. 109). Males, however, are often confused with C. impressa and C. longula. Compared to C. impressa, the sternites are usually brighter red and the black spots of S2 larger (Fig. 129), the mandible thicker (Fig. 146) and the transition of the lateral margin of T3 into the lateral apical teeth is straighter (not concave) (Fig. 87). Compared to C. longula (Fig. 161), the middle part of the pronotum is not as sharply darker than the margins (Fig. 160), the lateral margins of T3 are straighter, the punctation of T2 is usually finer anteriorly, and the central interval of the apical teeth is more angled (Fig. 87). In both sexes, the head and mesosoma are dorsally dark blue or nearly black with light blue or greenish reflections mainly on the pronotum. The tergites and sternites are red. The body is elongate and often rather large.
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood. Adults often fly near dead tree trunks (Betula, Populus, Salix) and close to walls of wooden buildings (log barns, sheds etc.), and they are also attracted to honeydew of aphids. Flight period: late May to late August. Host: possibly Ancistrocerus trifasciatus (Müller) (Vespidae) (our own obs.).

Diagnosis.
Length 6-9 mm. The species can be confused with several other similarly coloured species of the C. ignita group (e.g. C. leptomandibularis, C. schencki and C. corusca). Compared to C. leptomandibularis and C. schencki, the mandible is thicker, the punctation of T2 is finer, the black spots of S2 are more rectangular and the posterior margin of the propodeal tooth is directed more downward. Compared to C. corusca, the mandible is thinner, the punctation of the tergites is finer and the colour of the sternites is more reddish (not green). The head and mesosoma are mainly dark blue, and usually have extensive green or golden reflections on the frons, pronotum, mesopleuron, mesoscutum and mesoscutellum, especially in the female. The metasomal tergites are golden red (Fig. 99) and the sternites golden or reddish (Figs 119,  126). The black spots of S2 are characteristically rectangular in shape (Figs 119, 126). The body is elongate and slender, with parallel sides (resembling C. leptomandibularis) (Fig. 99). The punctation of T2 is fine, and its surface is strongly shining posteriorly (Fig. 99). T3 is relatively long, and strongly shining, especially in the female (Fig. 99). The apical teeth are short, and the central interval is wide and shallow (Figs 86, 99). The ovipositor is narrow (as in Fig. 92) and the mandible relatively thick in both sexes.

Diagnosis.
Length 10-13 mm. The body is elongate with parallel sides (Fig. 102) and usually large compared to other species of the C. ignita group. The head and mesosoma are dorsally blue or black, and the female has extensive golden green reflections on the pronotum, mesopleuron and mesoscutellum. The punctures of the mesoscutum are usually lighter coloured than the interstices (as in C. impressa). The tergites and sternites are golden red (Figs 102,121) and the black spots of S2 are long and narrow (Fig. 121). The punctation of T2 is anteriorly very coarse, and the surface of T3 is shiny in the female (Fig. 102). The mandible is long and relatively thick (in the male as in Fig 146). Small specimens can be confused with C. angustula and C. corusca, but the punctation of T2 is coarser anteriorly and the black spots of S2 are narrower. The sternites are mostly red, not greenish as in C. corusca. The males are often difficult to distinguish from C. impressa and C. subcoriacea. Compared to C. impressa, the sternites are usually brighter red and the black spots of S2 are more elongate. The punctation of T2 is coarser anteriorly and the metasoma is more elongate in shape. Compared to C. subcoriacea, the pronotum is more abruptly bicoloured (Fig. 161), the punctation of T2 is usually coarser anteriorly, the lateral margin of T3 is more concave and the central interval of the apical teeth is more arcuate (Fig. 88).
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood. Adults can be found on walls of old log buildings (barns, sheds etc.), log piles, poles and dead tree trunks (e.g. Betula, Populus, Salix). Flight period: early June to late August. Host: Ancistrocerus antilope (Panzer), Symmorphus crassicornis (Panzer) and S. murarius (Linnaeus) , Heinrich 1964, Morgan 1984, Brechtel 1985, Petit 1987, Martynova and Fateryga 2015, possibly also Ancistrocerus parietinus (Linnaeus) and species of Euodynerus Dalla Torre (Vespidae) (Blüthgen 1961, Morgan 1984, Martynova and Fateryga 2015. Remarks. Eastern Palearctic populations of C. longula belong to ssp. aeneopaca Linsenmaier, 1959 which differs from the nominotypical subspecies by having fine punctation and brownish colour anteriorly on tergites. Specimens of ssp. aeneopaca can sometimes be confused with C. subcoriacea. One specimen similar to ssp. aeneopaca has been found in Finland (Kuopio), but the occurrence of the taxon in Fennoscandia is questionable . Thomson, 1870 Figs 155, 157, 172 Chrysis brevitarsis Thomson, 1870: 107. Diagnosis. Length 7-10 mm. The species is characterised by its subapically toothed mandible (Fig. 155), which is unique among the Nordic and Baltic species of the C. ignita group. The head and mesosoma are mainly dark blue with greenish reflections, and the metasoma is dorsally golden red or dark red. As in C. pseudobrevitarsis, the spurs of the mesotibia are approximately equal in length (Fig. 167) and the mandible is very thick (medial width more than half of its basal width in the female and more than two thirds of the basal width in the male). In the female, the metatarsus is not longer than the metatibia (Fig. 169) and the antenna is strongly nodular (Fig. 172). The punctation of T2 and the mesoscutum (Fig. 157) is sparser compared to C. pseudobrevitarsis. Distribution. Estonia, Finland, Lithuania, Sweden. Rare. -West Palearctic: northern and central Europe (Linsenmaier 1997).
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood. Adults occasionally visit flowers of Apiaceae (Petit 1987 (Pärn et al. 2014, our own obs.), but probably also E. quadrifasciatus (Fabricius) and Ancistrocerus antilope (Panzer) (Vespidae) (Heinrich 1964, Morgan 1984, Martynova and Fateryga 2015. Linsenmaier, 1951 Fig. 100 Chrysis ignita var. mediata Linsenmaier, 1951: 76. Chrysis mediata: Linsenmaier 1959 Diagnosis. Length 6-10 mm. C. mediata and C. solida are closely related sibling species, which differ from other similarly coloured species of the C. ignita group by the combination of the following characters: 1) the ovipositor is broad (Figs 91, 100), 2) the inner margin of the paramere is angled (Fig. 137) and 3) the spurs of the mesotibia are of unequal length (as in Fig. 168). Both species are also characterised by the greenish sternites, the rounded or slightly rectangular black spots of S2 (Figs 120, 125), the relatively thick mandible, and the fine and dense punctation of T2, especially in the female (Figs 100, 101). C. mediata is often very difficult to differentiate from C. solida, but generally the body is larger and broader (Fig. 100), the head is narrower in frontal view (only slightly broader than high), the surface of T3 is shinier and the colour of the head and mesosoma is predominantly lighter blue. The colour of the tergites is golden red or dark red (Fig. 100), as in C. solida  .

Diagnosis.
Length 5-9 mm. The species is closely related to C. mediata, but the body is usually smaller and with more parallel sides (Fig. 101), the head is broader in frontal view (distinctly broader than its height), the punctation of T2 is often somewhat denser anteriorly (Fig. 101), the surface of T3 is not as shiny (Figs 101) and the colouration is predominantly darker. The species can be confused also with e.g. C. schencki, C. angustula and C. corusca. However, the ovipositor is broader (Fig. 91) and the inner margin of paramere is angled (Fig. 137) (not rounded). Also the green-blue colouration of S2 and the rounded shape of the black spots (Fig. 120, 125) are characteristic for C. solida. Distribution. Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Common. -Trans-Palearctic: from western Europe to Japan .
Remarks. C. solida and C. mediata are very similar morphologically and genetically despite clear differences in their biology and host selection . Reliable species identification is not always possible without information on the host or habitat. Niehuis, 2000 Figs 118, 127, 142, 145 Chrysis leptomandibularis Niehuis, 2000: 192. Diagnosis. Length 5-8 mm. The size and shape of the body are similarly slender and elongate as in C. angustula. However, the flagellomeres are shorter, S2 is greenish (not reddish) with shorter black spots (Figs 118,127) and the mesoscutum has wider, strongly shining interstices between the punctures in the female. The mandible is extremely thin in the female (medial width less than one third of its basal width) (Fig. 142) and somewhat thicker in the male (medial width about one third of its basal width) (Fig. 145). Compared to C. schencki, the mandible is thinner, the punctation of the mesoscutum is sparser and the body is more slender.

Chrysis schencki
The body shape is more elongate than in C. ignita, C. impressa and C. borealis sp. n., but not as slender as in C. angustula and C. leptomandibularis. Females are usually best distinguished from other species of the C. ignita group by their thin and basally concave mandible (Fig. 143), though males are more difficult to identify. Compared to C. impressa and C. borealis sp. n., the mandible of male is slightly thinner and basally more concave (Fig. 148), the body is more slender, and the relative length of F1 to F2 is somewhat smaller (Fig. 176). Identification of the males is not always possible with certainty by morphological characters alone.
Remarks. Recent mitochondrial DNA studies have shown that C. schencki consists of two distinct and sympatric genetic lineages in northern Europe . It is possible that they represent two different species, but more morphological and molecular studies are needed. Figs 104,105,122,130,147,163,175 Sphex ignita Linnaeus, 1758: 571. Chrysis ignita: Linnaeus 1761: 414. Chrysis ignita form B sensu Linsenmaier 1959: 156.

Diagnosis.
Length 5-10 mm. C. ignita resembles closely C. terminata in colouration, structure and habitus, but the frontal carina is shallowly M-shaped or more or less arcuate (not forming four tooth-like tubercles). The head and mesosoma are dorsally shiny blue or violet with green reflections on the pronotum and mesoscutellum (Fig. 163). The punctures of the mesoscutum are of the same colour as the interstices (Fig. 163) (not lighter as in C. impressa). The tergites are golden red (Figs 104, 105), the sternites green or blue (Figs 122,130) and the black spots of S2 are subrectangular in shape (Figs 120, 130). The punctation of T2 and T3 is coarse and regular (Figs 104, 105) and the apical teeth are sharply produced (Figs 104, 105). The medial furrow of the pronotum is narrow (Fig.  163) and the pubescence of the vertex is white (Fig. 147) or sometimes brown in the male.
Distribution. Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Relatively rare. -West Palearctic: from western Europe to central Asia and China ).

Biology.
Habitat: gardens, parks and forest margins. Adults are usually collected from walls of old buildings (both wooden and stone), dead tree trunks, poles and log piles. They rarely visit flowers of Apiaceae (Rosa 2004). Flight period: late May to early September. Host: probably Ancistrocerus parietum (Linnaeus) (Vespidae) (our own obs.). Numerous host records have been published for C. ignita, but most of these are unreliable, due to inconsistent taxonomic treatment of the species.
Remarks. A few studied specimens from Norway, Finland and Lithuania differ significantly from other North European C. ignita specimens based on their mitochondrial DNA sequences. According to Soon et al. (2014), they could represent a cryptic species ("Chrysis sp.1"). No distinct morphological differences have been found between the two North European genetic forms. Schenck, 1856 Figs 10, 84, 85, 92, 107, 108, 116, 132, 149, 164, 168, 170, 177 Chrysis impressa Schenck, 1856: 29. Chrysis ignita var. aurifera Linsenmaier, 1951 Diagnosis. Length 6-11 mm. The species is easily confused with other similarly coloured species of the C. ignita group and a combination of different diagnostic characters should be used in species determination. The head and the mesosoma are dorsally dark blue or black, and in the female the pronotum, mesopleuron and mesoscutellum have extensive golden green reflections (Fig. 164). The mesoscutum of the female is characteristically black, dark grey or olive coloured with contrastingly green or blue punctures (similar to C. longula) (Fig. 164). The mesoscutum of the male is often entirely dark blue or blue-violet. The tergites are golden red and relatively finely punctured (Figs 107, 108). The sternites are at least partially red-golden (Figs 116,132) and the black spots of S2 are usually roundish in the female (Figs 116). The setae on the dorsal surface of the head are brownish in both sexes (Fig. 149). The mandible is relatively thick (medial width about half or nearly half of basal width) and basally with only slightly concave margins (Figs 141, 149). F1 is long and narrow, about 1.4 times as long as F2 in the female and at least 1.2 times as long as F2 in the male (Fig. 177).

Diagnosis.
Length 6-11 mm. The species is very similar to C. impressa in shape and structure, but the colouration is darker and the length of F1 compared to F2 is larger (Table 1). The mesoscutum of the female is usually black, violet or dark blue with relatively fine and dense punctation (Figs 158, 179). The punctures are generally of the same colour as the interstices. The metasoma has golden red or reddish tergites (Figs 106,179) and the sternites are dark green or bluish in the female (Fig. 124), but often with golden red colour in male (Fig. 133). Compared to C. corusca, the body shape is stouter, the metasoma is notably swollen (Figs 106, 179), the black spots of S2 are broader (Figs 124, 133) and the mandible is thinner. Dark specimens of C. schencki are also very similar, but have a thinner mandible and coarser punctation on the scapal basin, and are more slender in habitus. The males of C. borealis in particular are difficult to distinguish from C. impressa and C. schencki. On average, the length ratio F1/F2 is larger (1.3-1.5:1) (Fig. 178, Table 1), the black spots of S2 are larger (Fig. 133) and the punctation of the mesoscutum is finer in C. borealis. Identification of the males is not always possible with certainty.
Mesosoma. Length 3.0-3.8 mm, width anterior to tegulae 2.0-2.7 mm. Length of pronotum medially 0.5-0.6 mm and width at anterior margin 1.8-2.2 mm. Colour of pronotum medially black, dark violet or dark blue, on the margins lighter green, blue or violet, only rarely with golden reflections (Figs 158, 179). Medial groove relatively shallow and indistinctly delimited. Mesoscutum dark violet or black, sometimes with bluish reflections (Figs 158, 179). Punctures generally of the same colour as interstices. Punctation of mesoscutum relatively fine and dense with narrow interstices (Figs 158,  179). Size of punctures on average smaller than in C. impressa and C. schencki. Interstices with scattered small punctures. Tegula green, blue or violet, with paler colour laterally. Mesoscutellum black medially and violet, blue, or sometimes greenish laterally, with irregular large punctures. Metanotum and propodeum violet, blue or green- Table 1. Length ratio of the first and second flagellomere in Chrysis borealis sp. n. and closely related species. All specimens of C. borealis sp. n. and C. impressa, and most of C. schencki were identified by DNA barcoding. In C. ignita, most specimens were identified by morphological characters only. A T-test was used for studying statistical differences between species. ish. Outer margin of lateral propodeal teeth straight or slightly concave. Pubescence on mesosoma whitish. Legs violet, blue or greenish, but tarsal segments dark brown. Wing venation as in C. impressa and C. schencki.  mm, maximum width 2.4-2.9 mm. Colour of tergites golden red or reddish, T1 anteriorly often greenish (Fig. 106). T1 with strong punctation, a weakly elevated medial line with sparser punctation, and very small and scattered punctures on interstices. Punctation of T2 anteriorly regular and dense, of the same strength as on T1 (Fig. 106). Punctation becoming weaker and more scattered laterally and posteriorly. T2 with prominent elevated medial line, anteriorly narrow and posteriorly broad, flat and shiny. T3 weakly saddle-shaped, with regular, strong and dense punctation, and often with elevated midline. Punctures of T3 on average as large as posteriorly on T2. Interstices usually with prominent microsculpture, whereby surface appears dull (Fig. 106). Posterior margin of T3 with four broadly separated teeth, intervals shallow. Medial interval usually about 1.5 times wider than lateral intervals. Subapical pit row with 15-20 black or bluish pits. Subapical lateral swellings relatively strong. Pubescence silvery white. Sternite colour green or blue, occasionally with golden reflections (Fig. 124). Black spots of S2 relatively large and subrectangular, their margins often vaguely delimited (Fig. 124). Ovipositor thin, similar to C. ignita and C. impressa (Fig. 92). Internal sternites and tergites similar to C. impressa (Figs 180-186). T5 relatively narrow, about three times as long as broad, and tapering posteriorly, without lateral stigmae (Fig. 181).
Mesosoma. Length 2.5-3.5 mm, width anterior to tegulae 1.7-2.4 mm. Length of pronotum medially 0.3-0.6 mm and width at anterior margin 1.5-2.1 mm. Structure as in female, but colouration usually somewhat lighter and pubescence longer. Margins of pronotum more often with golden reflections, and mesoscutum sometimes entirely blue. Mesoscutellum often medially violet, not always black, whereas mesoscutellum laterally, metanotum and propodeum violet, blue or golden green. Legs green, golden green or bluish with dark brown tibiae.  mm, maximum width 2.1-2.8 mm. Colour of tergites as in female, but punctation of T1 and T2 usually denser and finer. T3 with very dense and homogenous punctation. Interstices shining without distinct microsculpture. T3 convex, not medially depressed as in female. Shape of apical teeth of T3 relatively variable. Medial interval narrower than or as wide as lateral intervals. Subapical pit row with 12-20 black pits. Subapical lateral swellings weak or nearly missing. Sternites with green, golden and reddish colour (Fig. 133), sometimes almost completely green. Black spots of S2 large and rounded (Fig. 133). Inner margin of paramere rounded (Fig. 136). Internal sternites and tergites similar to . S8 about 1.2 times as long as broad, posteriorly pointed and anteriorly rounded (Fig. 195).
Geographic variation. Southern specimens from Estonia, Öland and Gotland are more uniform in colour than specimens from Finland, Norway and the Swedish mainland. The mesosoma of southern specimens is uniformly bright blue or violet with some greenish reflections, whereas in northern specimens, the mesoscutum and central part of the pronotum are commonly black or dark violet, and the margins of the pronotum and mesoscutellum are, in contrast, greenish or even golden green, especially in the males.
DNA analysis. Variable positions of the DNA barcode sequences of C. borealis sp. n. and its sibling species, C. ignita and C. impressa, are presented in Table 2. Despite relatively high intraspecific variability, there are two diagnostic nucleotide mutations conserved in all sequences of C. borealis sp. n. compared to C. ignita and C. impressa: G instead of A in position 241 and T instead of C in position 340. Additionally, there are three transitions shared with C. impressa, but differing from C. ignita, and one transition shared with C. ignita, but differing from both haplotypes of C. impressa. All samples of C. borealis sp. n. cluster together indicating their closer relationship with each-other than the other two species (Fig. 196).
Distribution. Denmark, Estonia, Finland, Norway, Sweden. Rare. -West Palearctic (?), general distribution poorly known. So far only known from the Nordic and Baltic countries and north-western Russia (Leningrad Oblast, Republic of Karelia, Murmansk Oblast) ).
Biology. Habitat: rocky outcrops, cliffs, alpine meadows, forest margins. Often found on islands of the Baltic Sea and in Lapland, where other species of the C. ignita group are uncommon. Adults have been found sitting on sun-exposed leaves of Tussilago and flowers of Apiaceae. They have also been collected using yellow pan traps. Flight period: late May to late August. A few specimens have been collected in early May and September. Host: Ancistrocerus parietum (Linnaeus) (Vespidae), based on records of C. borealis sp. n. from islands and other coastal localities, where A. parietum is the only species of Eumeninae. In northern alpine areas, where A. parietum is not present, A. scoticus (Curtis) is the most likely host species.
Etymology. The species epithet borealis is a Latin word derived from the Greek boreas which means north. We use it here as an adjective in the feminine case. The interpretation of borealis should be "northern".
Remarks. C. borealis sp. n. is very closely related to C. impressa, and cannot always be determined with certainty by morphological characters only. It is also easily confused with C. schencki. The colouration of C. impressa can sometimes be relatively dark and similar to C. borealis n. sp., which possibly could be caused by cool weather during the larval and pupal development. Generally, the colouration of chrysidids becomes darker in northern and alpine localities with cool climatic conditions. C. borealis n. sp. is mainly found in cooler habitats than C. impressa, so it could be claimed to constitute only a dark ecological form of C. impressa and not a distinct species. The slight,  Paukkunen) but constant divergence in the DNA barcode sequence (Table 2) and the statistically significant difference in the F1/F2 ratio (Table 1), however, supports the treatment of C. impressa and C. borealis n. sp. as distinct, but evolutionarily young sibling species. It is also noteworthy that the DNA barcode sequence of C. ignita is very similar to C. borealis n. sp. and C. impressa (Table 2), but due to significant morphological and ecological differences C. ignita undoubtedly forms a distinct species. Previous studies indicate that morphological and molecular differences between biologically welldefined species can be extremely small or even nonexistent in the C. ignita group ). An example is provided by C. mediata and C. solida, which are not always reliably separable by morphological characters or DNA barcodes, but represent ecologically well separated species with different hosts and habitats .
Several authors have earlier identified specimens of C. borealis sp. n. erroneously as C. mediadentata Linsenmaier, 1951). For example, Erlandsson

Diagnosis.
Length 6-10 mm. The species resembles closely C. ignita by its colour, structure and habitus. However, the frontal carina has medially four tooth-like tubercles in both sexes (Figs 153, 154), the mesosoma is more homogeneously blue without extensive green areas on the pronotum and the mesoscutellum, and the body is slightly more elongate with more parallel sides.
Distribution. Latvia, Lithuania, Norway, Sweden. Relatively common (especially in south-eastern Sweden, Öland and Gotland). -West Palearctic: from western Europe to central Asia .
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood, but also sparsely vegetated sandy areas. Flight period: late April to early August. The flight begins earlier than in other species of the C. ignita group. Host: Ancistrocerus nigricornis (Curtis) (Vespidae) ( van Lith 1954, our own obs.).

Diagnosis.
Length 7-11 mm. The species is easily recognised due to its unique combination of a red metasoma and six apical teeth. The head and the mesosoma are greenish, dark blue or nearly black with coppery reflections, whereas the metasoma is dorsally purple-red or coppery red. The tergites are coarsely punctured, and the posterior margin of T3 has six sharp teeth (Fig. 81). The shape of the body is robust and compact.

Diagnosis.
Length 7-10 mm. Both sexes have a mostly dark blue or black, partially violet, body with green reflections on the frons, margins of the pronotum, mesoscutum, mesoscutellum and mesopleuron. The tergites have contrasting golden red or golden green bands posteriorly (except on the apical rim), which are especially wide laterally on T1 and T2. The colour and form of the bands is quite variable, usually they are wider and more reddish in the female than in the male. The species closely resembles C. zetterstedti, but is characterised by the following differences: the black spots of S2 are narrower, usually not extending to the lateral margins of the sternite (Fig. 112), T5 of the female (on ovipositor) is broader and has a longitudinal medial groove (Fig. 89), the head is broader, especially in female (shortest distance between the compound eyes is slightly longer than the diameter of an eye) (Fig. 151), the gonostyle is shorter, the cuspis is apically curved (not straight) (Fig. 134), and the propodeal tooth is slightly convex or straight ventrally (not lobate).

Diagnosis.
Length 6-9 mm. The species resembles C. equestris, but differs from it by the following characters: the black spots of S2 are broader, extending to the lateral and anterior margins of the sternite (Fig. 113), T5 of the female is narrower and does not have a longitudinal medial groove (Fig. 90), the head is narrower (the shortest distance between the compound eyes is shorter or as long as the diameter of an eye) (Fig. 152), the gonostyle is more elongated, as long as the cuspis, the cuspis is apically straight (not curved) (Fig.  135), and the propodeal tooth is weakly lobate ventrally (not convex or straight).
Distribution. Estonia, Latvia, Lithuania, Sweden. Rare. -Trans-Palearctic: from North Europe to Siberia. Records from the East Palearctic Region refer to C. fasciata daphne Smith, 1874).
Biology. Habitat: forest margins and clearings with sun-exposed dead tree trunks and stumps (e.g. Quercus). Flight period: probably similar to that of C. equestris, most specimens have been collected in July. Host: unknown, possibly Euodynerus notatus (Jurine) (N. Johansson pers. obs.).
Remarks. Several authors have considered C. zetterstedti to be either a synonym (e.g. Trautmann 1927, Kimsey andBohart 1991) or a subspecies , Rosa and Soon 2012 of C. fasciata. However, molecular and morphological studies have shown that C. zetterstedti most likely represents a valid species ).
The occurrence of C. zetterstedti in central and southern Europe is still uncertain.  Trichrysis Lichtenstein, 1876: 27.

Note.
In Europe, this genus is characterised by the tridentate posterior margin of T3 (Figs 197,198), the medially located small black spots of S2 (Fig. 199), and the simple metanotum (Kimsey and Bohart 1991). The European species are relatively small (body length ca 4-8 mm) and completely blue or green in colour. Small males are often blackish, at least dorsally. The hosts are cavity-nesting crabronid and pompilid wasps, and possibly also solitary vespid wasps and megachilid bees (Trautmann 1927, Pärn et al. 2014). The genus includes 27 species in the Palearctic, Afrotropical and Oriental Regions Bohart 1991, Strumia 2009). Three species have been found in Europe (Rosa and Soon 2012), and one, T. cyanea, from the Nordic and Baltic countries ).

Diagnosis.
Length 4-8 mm. The species is characterised by its completely green, blue or violet body ( Fig. 197) and the tridentate posterior margin of T3 (Fig. 198). The male in particular is often dorsally or rarely almost completely black. The lateral teeth of T3 are often more like angles, and sometimes all teeth can be small or rounded and inconspicuous. The black spots of S2 are small and located close together (Fig. 199).
Biology. Habitat: forest margins, clearings and gardens with sun-exposed dead wood (e.g. dead tree trunks, log and branch piles, walls of wooden buildings or poles). Adults occasionally visit flowers of Apiaceae and Rosaceae (Kusdas 1956, Rosa 2004, our own obs.). Flight period: late May to early September. Host: primarily species of Trypoxylon Latreille (Crabronidae), but also Auplopus carbonarius (Scopoli) and species of Dipogon Fox (Pompilidae), and possibly other cavity-nesting crabronid wasps (Dufour and Perris 1840, Morgan 1984, Brechtel 1986, Asís et al. 1994, Gathmann and Tscharntke 1999, Tormos et al. 1996, Pärn et al. 2014, our own obs.). Also many cavity-nesting solitary bee species have been reported as hosts, but these records are rather unreliable due to the very different biology of bees compared to crabronid and pompilid hosts.

Note.
Diagnostic characters of this genus include the nearly flat and densely punctate frons, the lack of a transverse frontal carina (Figs 201,202), and the long malar space. Usually the mandible is also toothed subapically (Fig. 202), the proximal flagellomeres of the male are swollen ventrally ( Fig. 204) and the pronotum is shorter than the mesoscutellum. The radial cell of the forewing is closed and the posterior margin of T3 is rounded without apical teeth . Chrysura is the second largest genus in the tribe Chrysidini. It includes 117 valid species, of which 106 are distributed in the Palearctic Region Bohart 1991, Rosa and. The hosts consist of solitary bees of the family Megachilidae. The European fauna includes 50 species and several subspecies (Rosa and Soon 2012). Five species have been recorded in the Nordic and Baltic countries ). Species-groups below follow Kimsey and Bohart (1991).

Diagnosis.
Length 8-12 mm. The species differs from other similarly coloured species of Chrysura by its ventrally broader head (Fig. 201) and simple mandible, which lacks or has only a very small subapical tooth (Fig. 201). The antennal segments of the male are not ventrally swollen. The head and mesosoma are blue, often with golden green reflections laterally on the mesoscutum, and the metasoma is golden red. Distribution. Lithuania. Very rare. The species is known from three localities in Lithuania (Puvočiai, Trakai, Vilnius) (Orlovskytė et al. 2010). -Trans-Palearctic: from Europe and northern Africa to Siberia and Japan (Linsenmaier 1997, Kurzenko andLelej 2007).

Chrysura trimaculata (Förster, 1853) Figs 205, 206
Chrysis trimaculata Förster, 1853: 307. Chrysura trimaculata: Kimsey and Bohart 1991: 497. Diagnosis. Length 9-11 mm. Compared to other similarly coloured species of Chrysura, the metascutellum is more sharply elevated (Fig. 205) and T3 of the female is longer and more ovoid in shape (Fig. 206). Punctation of the tergites is very dense and homogeneous (Fig. 206). The black spots on S2 are very large, and the eyes are strongly bulging above genae. The head and mesosoma are dark green or green-blue and the metasoma is golden red.
Distribution. Sweden. Rare. Only found on the islands of Öland and Gotland. -West Palearctic: southern and central Europe, Asia Minor .

Tribe Parnopini
This tribe has been treated as a valid subfamily, Parnopinae, by several authors (Mocsáry 1889, , Mingo 1994. We follow the classification of Kimsey and Bohart (1991) and include it in the Chrysidinae. Parnopini is characterised by several morphological features, such as the strongly developed mouthparts, the large and broad tegula which covers the wing basally, the irregularly and finely dentate posterior margin of the last external tergite, and the number of exposed metasomal tergites, which is four in the male and three in the female. The tribe consists of three genera, one of which, Parnopes, is found in Europe.

Note.
The genus can be distinguished from other genera of Parnopini by the reduced palpi, the large metascutellar projection and the larger body size. Members of the genus are parasites of ground-nesting solitary wasps of the tribe Bembicini (Crabronidae: Bembicinae). A total of 16 species are recognised, most of which occur in the Palearctic and Nearctic Regions (with 4 and 7 species, respectively) (Kimsey and Bohart 1991). A few species are known from India and Africa. Only one species, P. grandior, is found in Europe (Rosa and Soon 2012). The genus has been divided into species-groups by Kimsey and Bohart (1991).

Diagnosis.
Length 8-12 mm. The species is easy to differentiate from other North European cuckoo wasps by its unique structure and colouration. The head, mesosoma and most of T1 are green or green-blue, with golden or coppery reflections, especially in the female. The metasoma behind T1, tegulae and tibiae are usually non-metallic red (Fig. 209). Sometimes also T2, T3 (and T4) have a metallic sheen laterally or even dorsally. The female has three and the male four external tergites, and the posterior margin of the last tergite is irregularly dentate (Fig. 209). The mouthparts are longer than the rest of the head, and the tegulae are large covering the wing bases (Fig. 209).