Four new species of Diglyphomorphomyia Girault (Hymenoptera, Eulophidae) from China, with a key to Chinese species.

Four new species of Diglyphomorphomyia Girault, D.depressa sp. nov., D.fossa sp. nov., D.hainana sp. nov., and D.octoseta sp. nov., are described from China. A key to the eight species of the genus Diglyphomorphomyia occurring in China is provided.

Two new species of Deutereulophus Schulz (Hymenoptera, Eulophidae) from China, with a key to Chinese species.

Two new species of Deutereulophus Schulz, D.felix sp. nov. and D.daguisiensis sp. nov., are described from China. A key to species of Deutereulophus known from China is provided.

Two new species of Hemiptarsenus Westwood (Hymenoptera, Eulophidae) from China, with a key to Chinese species.

Two new species of Hemiptarsenus Westwood, H.tianshuiensis sp. nov. and H.longjiangensis sp. nov., are described from China. New distributional data for H.jilinus Tao, 2021 are provided, and a key to Chinese species of the genus is given based on females.

Three new species of Stenomesius Westwood (Hymenoptera, Eulophidae) from China, with a key to Chinese species.

Three new species of Stenomesius Westwood, S.guanshanensis sp. nov., S.hani sp. nov., and S.harbinensis sp. nov., are described from China. A key to all species of the genus Stenomesius in China is provided.

A new species of Hemiptarsenus Westwood (Hymenoptera, Eulophidae) from China, with a key to Chinese species.

A new species, Hemiptarsenus jilinus Tao, sp. nov., is described and illustrated. All the type specimens were reared from Chromatomyia horticola (Goureau) (Diptera: Agromyzidae), a leafminer attacking the plants Ixeris polycephala Cass. and Pterocypsela indica (L.) Shih, in Jilin Province, north-eastern China. A key to Chinese species of the genus is provided.

A new species of Pnigalio (Hymenoptera, Eulophidae) parasitizing Eriocrania semipurpurella alpina (Lepidoptera, Eriocraniidae) in China, with its biology and a key to Chinese known species.

A new species of Eulophinae, Pnigalio eriocraniae Li & Yang, sp. n., is described and illustrated. This new species is a larval ectoparasitoid of Eriocrania semipurpurella alpina Xu (Lepidoptera, Eriocraniidae), a leaf miner in birch trees, Betula spp. (Betulaceae), in Qinghai Province, northwest China. The biology of the new species and a key to the known species from China are provided.

Integrative taxonomy of New World Euplectrus Westwood (Hymenoptera, Eulophidae), with focus on 55 new species from Area de Conservación Guanacaste, northwestern Costa Rica.

90 species of Euplectrus are treated: 55 newly described, all from Area de Conservación Guanacaste (ACG), and 35 previously described species, of which 20 occur in ACG. Three of the previously described species (Euplectrusbrasiliensis Ashmead, Euplectrushircinus (Say), Euplectrusronnai (Brèthes)) have unknown status, owing to missing or severely damaged type material. The new species, all authored by C. Hansson, are: Euplectrusalejandrovalerioi, Euplectrusalexsmithi, Euplectrusalvarowillei, Euplectrusandybennetti, Euplectrusandydeansi, Euplectrusannettewalkerae, Euplectrusbillbrowni, Euplectrusbobwhartoni, Euplectruscarlosarmientoi, Euplectruscarlrettenmeyeri, Euplectruscharlesmicheneri, Euplectruscharlesporteri, Euplectruschrisdarlingi, Euplectruschrisgrinteri, Euplectruscorriemoreauae, Euplectrusdaveroubiki, Euplectrusdavesmithi, Euplectrusdavidwahli, Euplectrusdianariasae, Euplectrusdonquickei, Euplectruseowilsoni, Euplectrusgarygibsoni, Euplectrusgavinbroadi, Euplectrusgerarddelvarei, Euplectrushenrytownesi, Euplectrushowelldalyi, Euplectrushugokonsi, Euplectrusiangauldi, Euplectrusjacklonginoi, Euplectrusjesusugaldei, Euplectrusjimwhitfieldi, Euplectrusjjrodriguezae, Euplectrusjohnheratyi, Euplectrusjohnlasallei, Euplectrusjohnnoyesi, Euplectrusjosefernandezi, Euplectruslubomirmasneri, Euplectrusmarkshawi, Euplectrusmikegatesi, Euplectrusmikeschauffi, Euplectrusmikesharkeyi, Euplectrusninazitaniae, Euplectruspammitchellae, Euplectruspaulhansoni, Euplectruspaulheberti, Euplectruspaulhurdi, Euplectrusphilwardi, Euplectrusrobbinthorpi, Euplectrusronaldzunigai, Euplectrusroysnellingi, Euplectrusscottshawi, Euplectrussondrawardae, Euplectrussydneycameronae, Euplectrusvictoriapookae, Euplectruswonyoungchoi. The species are described or redescribed, and thoroughly and uniformly illustrated, and included in two identification keys, one for females and one for males. Lectotypes are designated for eight species: Euplectruscatocalae Howard (♂), Euplectrusjunctus Gahan (♀), Euplectrusleucotrophis Howard (♂), Euplectrusmarginatus Ashmead (♀), Euplectruspachyscaphus Girault (♀), Euplectrusplatyhypenae Howard (♂), Euplectrussemimarginatus Girault (♀), Heteroscapusronnai Brèthes (♂). One synonym is established: Euplectruswalteri Schauff is a junior synonym of Euplectrustestaceipes (Cameron). Brief image notes and host records are provided on the natural history of the wasps as well as the details of their morphology. Hosts are known for 74 Euplectrus species.

First report of Elasmus polistis Burks (Hymenoptera: Eulophidae) recovered from Polistes versicolor (Olivier) (Hymenoptera: Vespidae) nests in Brazil

The first record of Elasmus polistis Burks in Polistes versicolor (Olivier) nests in the Rio Grande do Sul state and in Brazil is provided. A total of 173 specimens of P. versicolor and 790 specimens of E.polistis were collected from two nests from Gramado and Santa Cruz do Sul, RS, Brazil.