A checklist of world species of Microgastrinae parasitoid wasps (Hymenoptera: Braconidae) is provided. A total of 81 genera and 2,999 extant species are recognized as valid, including 36 nominal species that are currently considered asspecies inquirendae. Two genera are synonymized underApanteles. Nine lectotypes are designated. A total of 318 new combinations, three new replacement names, three species name amendments, and seven species status revised are proposed. Additionally, three species names are treated asnomina dubia, and 52 species names are considered as unavailable names (including 14 asnomina nuda). A total of three extinct genera and 12 extinct species are also listed. Unlike in many previous treatments of the subfamily, tribal concepts are judged to be inadequate, so genera are listed alphabetically. Brief diagnoses of all Microgastrinae genera, as understood in this paper, are presented. Illustrations of all extant genera (at least one species per genus, usually more) are included to showcase morphological diversity. Primary types of Microgastrinae are deposited in 108 institutions worldwide, although 76% are concentrated in 17 collections. Localities of primary types, in 138 countries, are reported. Recorded species distributions are listed by biogeographical region and by country. Microgastrine wasps are recorded from all continents except Antarctica; specimens can be found in all major terrestrial ecosystems, from 82°N to 55°S, and from sea level up to at least 4,500 m a.s.l. The Oriental (46) and Neotropical (43) regions have the largest number of genera recorded, whereas the Palaearctic region (28) is the least diverse. Currently, the highest species richness is in the Palearctic region (827), due to more historical study there, followed by the Neotropical (768) and Oriental (752) regions, which are expected to be the most species rich. Based on ratios of Lepidoptera and Microgastrinae species from several areas, the actual world diversity of Microgastrinae is expected to be between 30,000–50,000 species; although these ratios were mostly based on data from temperate areas and thus must be treated with caution, the single tropical area included had a similar ratio to the temperate ones. Almost 45,000 specimens of Microgastrinae from 67 different genera (83% of microgastrine genera) have complete or partial DNA barcode sequences deposited in the Barcode of Life Data System; the DNA barcodes represent 3,545 putative species or Barcode Index Numbers (BINs), as estimated from the molecular data. Information on the number of sequences and BINs per genus are detailed in the checklist. Microgastrinae hosts are here considered to be restricted to Eulepidoptera, i.e., most of the Lepidoptera except for the four most basal superfamilies (Micropterigoidea, Eriocranioidea, Hepialoidea and Nepticuloidea), with all previous literature records of other insect orders and those primitive Lepidoptera lineages being considered incorrect. The following nomenclatural acts are proposed: 1) Two genera are synonymyzed underApanteles:CecidobraconKieffer & Jörgensen, 1910,new synonymandHolcapantelesCameron, 1905,new synonym; 2) Ninelectotype designationsare made forAlphomelon disputabile(Ashmead, 1900),Alphomelon nigriceps(Ashmead, 1900),Cotesia salebrosa(Marshall, 1885),Diolcogaster xanthaspis(Ashmead, 1900),Dolichogenidea ononidis(Marshall, 1889),Glyptapanteles acraeae(Wilkinson, 1932),Glyptapanteles guyanensis(Cameron, 1911),Glyptapanteles militaris(Walsh, 1861), andPseudapanteles annulicornisAshmead, 1900; 3) Threenew replacement namesare a)Diolcogaster aurangabadensisFernandez-Triana, replacingDiolcogaster indicus(Rao & Chalikwar, 1970) [necDiolcogaster indicus(Wilkinson, 1927)], b)Dolichogenidea incystataeFernandez-Triana, replacingDolichogenidea lobesiaLiu & Chen, 2019 [necDolichogenidea lobesiaFagan-Jeffries & Austin, 2019], and c)Microplitis vitobiasiFernandez-Triana, replacingMicroplitis variicolorTobias, 1964 [necMicroplitis varicolorViereck, 1917]; 4) Threenames amendedareApanteles irenecarrilloaeFernandez-Triana, 2014,Cotesia ayerzai(Brèthes, 1920), andCotesia riverai(Porter, 1916); 5) Seven species have theirstatus revised:Cotesia arctica(Thomson, 1895),Cotesia okamotoi(Watanabe, 1921),Cotesia ukrainica(Tobias, 1986),Dolichogenidea appellator(Telenga, 1949),Dolichogenidea murinanae(Capek & Zwölfer, 1957),Hypomicrogaster acarnasNixon, 1965, andNyereria nigricoxis(Wilkinson, 1932); 6)New combinationsare given for 318 species:Alloplitis congensis,Alloplitis detractus,Apanteles asphondyliae,Apanteles braziliensis,Apanteles sulciscutis,Choeras aper,Choeras apollion,Choeras daphne,Choeras fomes,Choeras gerontius,Choeras helle,Choeras irates,Choeras libanius,Choeras longiterebrus,Choeras loretta,Choeras recusans,Choeras sordidus,Choeras stenoterga,Choeras superbus,Choeras sylleptae,Choeras vacillatrix,Choeras vacillatropsis,Choeras venilia,Cotesia asavari,Cotesia bactriana,Cotesia bambeytripla,Cotesia berberidis,Cotesia bhairavi,Cotesia biezankoi,Cotesia bifida,Cotesia caligophagus,Cotesia cheesmanae,Cotesia compressithorax,Cotesia delphinensis,Cotesia effrena,Cotesia euphobetri,Cotesia elaeodes,Cotesia endii,Cotesia euthaliae,Cotesia exelastisae,Cotesia hiberniae,Cotesia hyperion,Cotesia hypopygialis,Cotesia hypsipylae,Cotesia jujubae,Cotesia lesbiae,Cotesia levigaster,Cotesia lizeri,Cotesia malevola,Cotesia malshri,Cotesia menezesi,Cotesia muzaffarensis,Cotesia neptisis,Cotesia nycteus,Cotesia oeceticola,Cotesia oppidicola,Cotesia opsiphanis,Cotesia pachkuriae,Cotesia paludicolae,Cotesia parbhanii,Cotesia parvicornis,Cotesia pratapae,Cotesia prozorovi,Cotesia pterophoriphagus,Cotesia radiarytensis,Cotesia rangii,Cotesia riverai,Cotesia ruficoxis,Cotesia senegalensis,Cotesia seyali,Cotesia sphenarchi,Cotesia sphingivora,Cotesia transuta,Cotesia turkestanica,Diolcogaster abengouroui,Diolcogaster agama,Diolcogaster ambositrensis,Diolcogaster anandra,Diolcogaster annulata,Diolcogaster bambeyi,Diolcogaster bicolorina,Diolcogaster cariniger,Diolcogaster cincticornis,Diolcogaster cingulata,Diolcogaster coronata,Diolcogaster coxalis,Diolcogaster dipika,Diolcogaster earina,Diolcogaster epectina,Diolcogaster epectinopsis,Diolcogaster grangeri,Diolcogaster heterocera,Diolcogaster homocera,Diolcogaster indica,Diolcogaster insularis,Diolcogaster kivuana,Diolcogaster mediosulcata,Diolcogaster megaulax,Diolcogaster neglecta,Diolcogaster nigromacula,Diolcogaster palpicolor,Diolcogaster persimilis,Diolcogaster plecopterae,Diolcogaster plutocongoensis,Diolcogaster psilocnema,Diolcogaster rufithorax,Diolcogaster semirufa,Diolcogaster seyrigi,Diolcogaster subtorquata,Diolcogaster sulcata,Diolcogaster torquatiger,Diolcogaster tristiculus,Diolcogaster turneri,Diolcogaster vulcana,Diolcogaster wittei,Distatrix anthedon,Distatrix cerales,Distatrix cuspidalis,Distatrix euproctidis,Distatrix flava,Distatrix geometrivora,Distatrix maia,Distatrix tookei,Distatrix termina,Distatrix simulissima,Dolichogenidea agamedes,Dolichogenidea aluella,Dolichogenidea argiope,Dolichogenidea atreus,Dolichogenidea bakeri,Dolichogenidea basiflava,Dolichogenidea bersa,Dolichogenidea biplagae,Dolichogenidea bisulcata,Dolichogenidea catonix,Dolichogenidea chrysis,Dolichogenidea coffea,Dolichogenidea coretas,Dolichogenidea cyane,Dolichogenidea diaphantus,Dolichogenidea diparopsidis,Dolichogenidea dryas,Dolichogenidea earterus,Dolichogenidea ensiger,Dolichogenidea eros,Dolichogenidea evadne,Dolichogenidea falcator,Dolichogenidea gelechiidivoris,Dolichogenidea gobica,Dolichogenidea hyalinis,Dolichogenidea iriarte,Dolichogenidea lakhaensis,Dolichogenidea lampe,Dolichogenidea laspeyresiella,Dolichogenidea latistigma,Dolichogenidea lebene,Dolichogenidea lucidinervis,Dolichogenidea malacosomae,Dolichogenidea maro,Dolichogenidea mendosae,Dolichogenidea monticola,Dolichogenidea nigra,Dolichogenidea olivierellae,Dolichogenidea parallelis,Dolichogenidea pelopea,Dolichogenidea pelops,Dolichogenidea phaenna,Dolichogenidea pisenor,Dolichogenidea roepkei,Dolichogenidea scabra,Dolichogenidea statius,Dolichogenidea stenotelas,Dolichogenidea striata,Dolichogenidea wittei,Exoryza asotae,Exoryza belippicola,Exoryza hylas,Exoryza megagaster,Exoryza oryzae,Glyptapanteles aggestus,Glyptapanteles agynus,Glyptapanteles aithos,Glyptapanteles amenophis,Glyptapanteles antarctiae,Glyptapanteles anubis,Glyptapanteles arginae,Glyptapanteles argus,Glyptapanteles atylana,Glyptapanteles badgleyi,Glyptapanteles bataviensis,Glyptapanteles bistonis,Glyptapanteles borocerae,Glyptapanteles cacao,Glyptapanteles cadei,Glyptapanteles cinyras,Glyptapanteles eryphanidis,Glyptapanteles euproctisiphagus,Glyptapanteles eutelus,Glyptapanteles fabiae,Glyptapanteles fulvigaster,Glyptapanteles fuscinervis,Glyptapanteles gahinga,Glyptapanteles globatus,Glyptapanteles glyphodes,Glyptapanteles guierae,Glyptapanteles horus,Glyptapanteles intricatus,Glyptapanteles lamprosemae,Glyptapanteles lefevrei,Glyptapanteles leucotretae,Glyptapanteles lissopleurus,Glyptapanteles madecassus,Glyptapanteles marquesi,Glyptapanteles melanotus,Glyptapanteles melissus,Glyptapanteles merope,Glyptapanteles naromae,Glyptapanteles nepitae,Glyptapanteles nigrescens,Glyptapanteles ninus,Glyptapanteles nkuli,Glyptapanteles parasundanus,Glyptapanteles penelope,Glyptapanteles penthocratus,Glyptapanteles philippinensis,Glyptapanteles philocampus,Glyptapanteles phoebe,Glyptapanteles phytometraduplus,Glyptapanteles propylae,Glyptapanteles puera,Glyptapanteles seydeli,Glyptapanteles siderion,Glyptapanteles simus,Glyptapanteles speciosissimus,Glyptapanteles spilosomae,Glyptapanteles subpunctatus,Glyptapanteles thespis,Glyptapanteles thoseae,Glyptapanteles venustus,Glyptapanteles wilkinsoni,Hypomicrogaster samarshalli,Iconella cajani,Iconella detrectans,Iconella jason,Iconella lynceus,Iconella pyrene,Iconella tedanius,Illidops azamgarhensis,Illidops lamprosemae,Illidops trabea,Keylimepie striatus,Microplitis adisurae,Microplitis mexicanus,Neoclarkinella ariadne,Neoclarkinella curvinervus,Neoclarkinella sundana,Nyereria ituriensis,Nyereria nioro,Nyereria proagynus,Nyereria taoi,Nyereria vallatae,Parapanteles aethiopicus,Parapanteles alternatus,Parapanteles aso,Parapanteles atellae,Parapanteles bagicha,Parapanteles cleo,Parapanteles cyclorhaphus,Parapanteles demades,Parapanteles endymion,Parapanteles epiplemicidus,Parapanteles expulsus,Parapanteles fallax,Parapanteles folia,Parapanteles furax,Parapanteles hemitheae,Parapanteles hyposidrae,Parapanteles indicus,Parapanteles javensis,Parapanteles jhaverii,Parapanteles maculipalpis,Parapanteles maynei,Parapanteles neocajani,Parapanteles neohyblaeae,Parapanteles nydia,Parapanteles prosper,Parapanteles prosymna,Parapanteles punctatissimus,Parapanteles regalis,Parapanteles sarpedon,Parapanteles sartamus,Parapanteles scultena,Parapanteles transvaalensis,Parapanteles turri,Parapanteles xanthopholis,Pholetesor acutus,Pholetesor brevivalvatus,Pholetesor extentus,Pholetesor ingenuoides,Pholetesor kuwayamai,Promicrogaster apidanus,Promicrogaster briareus,Promicrogaster conopiae,Promicrogaster emesa,Promicrogaster grandicula,Promicrogaster orsedice,Promicrogaster repleta,Promicrogaster typhon,Sathon bekilyensis,Sathon flavofacialis,Sathon laurae,Sathon mikeno,Sathon ruandanus,Sathon rufotestaceus,Venanides astydamia,Venanides demeter,Venanides parmula, andVenanides symmysta.

The checklist of British and Irish Braconidae is revised, based in large part on the collections of the National Museums of Scotland, Edinburgh, and the Natural History Museum, London. Distribution records are provided at the country level together with extensive synonymy and bibliography. Of the 1,338 species regarded as valid, presumed native and certainly identified, 83 are here recorded for the first time from the British Isles. One new synonym is established (Dyscritus suffolciensis Morley, 1933 = Syntretus splendidus (Marshall, 1887) syn. nov.)

The parasitoid wasp family Ichneumonidae is arguably one of the groups for which current knowledge lags most strongly behind their enormous diversity. In a five-day meeting in Basel (Switzerland) in June 2019, 22 researchers from 14 countries met to discuss the most important issues in ichneumonid research, including increasing the speed of species discovery, resolving higher-level relationships, and studying the radiation of these parasitoids onto various host groups through time. All agreed that it is time to advertise ichneumonid research more broadly in the scientific community and thereby attract young talents to this group for which specialists are sorely lacking. In order to popularize the group, we here suggest a new name for the family, “Darwin wasps”, to reflect the pivotal role they played in convincing Charles Darwin that not all of creation could have been created by a benevolent god. We hope that the name catches on, and that Darwin wasps start buzzing more loudly across all disciplines of biology.

Substantial parts of the European and German insect fauna still remain largely unexplored, the so-called “dark taxa”. In particular, midges (Diptera) and parasitoid wasps (Hymenoptera) are abundant and species-rich throughout Europe, yet are often neglected in biodiversity research. One such dark taxon is Microgastrinae wasps (Hymenoptera: Braconidae), a group of parasitoids of lepidopteran caterpillars with 252 species reported in Germany so far. As part of the German Barcode of Life Project GBOL III: Dark Taxa, reverse DNA barcoding and integrative taxonomic approaches were used to shed some light on the German Fauna of Microgastrinae wasps. In our workflow, DNA barcoding was used for molecular clustering of our specimens in a first step, morphological examination of the voucher specimens in a second step, and host data compared in a third step. Here, 30 species are reported for the first time in Germany, adding more than 10% to the known German fauna. Information for four species is provided in a new Holarctic context, reporting them for the Nearctic or, respectively, Palaearctic region, and 26 additional country records are added from sequenced material available in the collections accessible to us. Molecular clusters that show signs of discrepancies are discussed. Results show that we are just scratching the tip of the iceberg of the unexplored Microgastrinae diversity in Germany.

The ophionine ichneumonid known as Hellwigiaobscura has been reared for the first time, from larvae of Horisme sp. (Lepidoptera: Geometridae) feeding on Clematisvitalba in The Netherlands. The cocoon and the parasitoid’s means of emergence are figured, as are some features of the adult. On a balance of morphological grounds, including some already discussed in the literature, it is proposed that “Hellwigia” obscura should be excluded from Hellwigia and instead be ascribed to the genus Heinrichiellastat. rev. as Heinrichiellaobscuracomb. n. Reasons for this change as well as for preferring this generic name to Protohellwigia Brues are given

Seven new species of the genus Aleiodes Wesmael, 1838 (Braconidae: Rogadinae) are described and illustrated: A. abraxanae sp. n., A. angustipterus sp. n., A. artesiariae sp. n., A. carminatus sp. n., A. diarsianae sp. n., A. leptofemur sp. n., and A. ryrholmi sp. n. A neotype is designated for each of Aleiodes circumscriptus (Nees, 1834) and A. pictus (Herrich-Schäffer, 1838), and both species are redescribed and illustrated. Aleiodes ochraceus Hellén, 1927 (not A. ochraceus (Curtis, 1834)) is renamed as A. curticornis nom. n. & stat. rev., and redescribed and illustrated. Aleiodes bistrigatus Roman, 1917, A. nigriceps Wesmael, 1838, and A. reticulatus (Noskiewicz, 1956), are re-instated as valid species. A lectotype is designated for Aleiodes bistrigatus Roman. An illustrated key is given to some distinctive species and the residual species groups along which further parts of an entire revision of western Palaearctic species of Aleiodes and Heterogamus will be organised. Biology, host associations and phenology are discussed for the keyed species (in addition to the above, A. albitibia (Herrich-Schäffer, 1838), A. apiculatus (Fahringer, 1932), A. arcticus (Thomson, 1892), A. cantherius (Lyle, 1919), A. esenbeckii (Hartig, 1834), A. jakowlewi (Kokujev, 1898), A. modestus (Reinhard, 1863), A. nigricornis Wesmael, 1838, A. pallidator (Thunberg, 1822), A. praetor (Reinhard, 1863), A. seriatus (Herrich- Schäffer, 1838) sensu lato, A. testaceus (Telenga, 1941), A. ungularis (Thomson, 1892), and A. varius (Herrich-Schäffer, 1838)) which are dealt with in full here (with the exception of A. seriatus s.l. which is, however, included in the key). The experimental methodology covering the revision as a whole, which involves some behavioural investigation, is outlined. Seven new species of the genus Aleiodes Wesmael, 1838 (Braconidae: Rogadinae) are described and illustrated: A. abraxanae sp. n., A. angustipterus sp. n., A. artesiariae sp. n., A. carminatus sp. n., A. diarsianae sp. n., A. leptofemur sp. n., and A. ryrholmi sp. n. A neotype is designated for each of Aleiodes circumscriptus (Nees, 1834) and A. pictus (Herrich-Schäffer, 1838), and both species are redescribed and illustrated. Aleiodes ochraceus Hellén, 1927 (not A. ochraceus (Curtis, 1834)) is renamed as A. curticornis nom. n. & stat. rev., and redescribed and illustrated. Aleiodes bistrigatus Roman, 1917, A. nigriceps Wesmael, 1838, and A. reticulatus (Noskiewicz, 1956), are re-instated as valid species. A lectotype is designated for Aleiodes bistrigatus Roman. An illustrated key is given to some distinctive species and the residual species groups along which further parts of an entire revision of western Palaearctic species of Aleiodes and Heterogamus will be organised. Biology, host associations and phenology are discussed for the keyed species (in addition to the above, A. albitibia (Herrich-Schäffer, 1838), A. apiculatus (Fahringer, 1932), A. arcticus (Thomson, 1892), A. cantherius (Lyle, 1919), A. esenbeckii (Hartig, 1834), A. jakowlewi (Kokujev, 1898), A. modestus (Reinhard, 1863), A. nigricornis Wesmael, 1838, A. pallidator (Thunberg, 1822), A. praetor (Reinhard, 1863), A. seriatus (Herrich- Schäffer, 1838) sensu lato, A. testaceus (Telenga, 1941), A. ungularis (Thomson, 1892), and A. varius (Herrich-Schäffer, 1838)) which are dealt with in full here (with the exception of A. seriatus s.l. which is, however, included in the key). The experimental methodology covering the revision as a whole, which involves some behavioural investigation, is outlined.