Palaearctic species of the sequester group of Pteromalus Swederus, 1795 are reviewed. Three new species, P. boleensis Yan, Li & Tselikh, sp. nov. (Kazakhstan, China), P. longipedicellus Yan, Li & Tselikh, sp. nov. (China) and P. oscolensis Tselikh, sp. nov. (Russia, China) are described and illustrated. Types of P. cionobia (Erdös, 1953) and P. sequester Walker, 1835 are redescribed. An identification key to females of the sequester group of Pteromalus is given.

Two new species of Pteromalus Swederus (Hymenoptera, Pteromalidae, Pteromalinae), Pteromalus steppensis Li & Hu, sp. nov. and Pteromalus xiaomoheensis Yan & Li, sp. nov., are described and illustrated for the first time. Pteromalus steppensis Li & Hu, sp. nov. was reared as a primary, solitary ectoparasitoid of the larval and pupal stages of Orchestes steppensis Korotyaev, 2016 (Coleoptera, Curculionidae). Figures of its development and its host damage are also provided.

The flea-weevil Orchestes steppensis Korotyaev (Coleoptera: Curculionidae) is an Eastern Palaearctic Steppe species, and a serious pest of elm trees (Ulmus spp., Ulmaceae) by feeding on the leaves (adults) or mining them heavily (larvae) in Xinjiang, China. In order to search for chemical and ecological pest management practices, the olfactory preferences of O. steppensis for leaves of three elm species were investigated. The results revealed that O. steppensis has different host preferences for the three elm species: U. pumila L. first, followed by Ulmus laevis Pall. and Ulmus densa Litw. last. Volatile organic compounds from the leaves of the three Ulmus species were collected using dynamic headspace adsorption and analyzed through gas chromatography–mass spectrometry (GC-MS). A total of 94 volatile components in the healthy leaves and the infested leaves by O. steppensis of the three elm species were identified and analyzed, and 13 active compounds were identified using coupled gas chromatography–electroantennographic (GC-EAD) recording and GC-MS analysis. The response of O. steppensis to different concentrations of active compounds was determined using EAG, and the behavioral response to the highest EAG concentration of each active compound was determined. The results demonstrated that 3-hexen-1-ol, 3,7-dimethyl-1,3,6-Octatriene, methyl salicylate, 1-hexanol, and 3-hexen-1-ol, acetate were attractive to O. steppensis, while nonanal and 2-hexenal were repellent.

A new species of the genus Marshiella Shaw, 1985 is described and illustrated from Xinjiang (NW. China): Marshiella baichengensis Amat & van Achterberg, sp. nov. In addition, a key to the ten known species and one new species in this genus is provided.

The hymenopteran parasitoid complex of the families Eurytomidae and Pteromalidae associated with Lixus subtilis Boheman, 1836 (Coleoptera, Curculionidae) developing on sugar beet is studied in China (Xinjiang region). Eurytoma curculionum Mayr, 1878 (Eurytomidae) was reared from the larvae of Lixus subtilis and recorded for Xinjiang, China, for the first time. A new species, Chlorocytus papahemii sp. nov . (Pteromalidae), a hyperparasitoid of E. curculionum , is described from China. Illustrations and a detailed morphological description of the new species, as well as a redescription of the types of related Chlorocytus species, are provided. An identification key for females of the Chlorocytus harmolitae species is given.

The genera Aphaereta Förster, 1863 (tribe Alysiini) and Elasmosoma Ruthe, 1858 (tribe Neoneurini, subfamily Euphorinae) represent two distinct and ecologically specialised lineages within the family Braconidae. Aphaereta is a cosmopolitan genus with approximately 48 described species worldwide, with four species recorded in China. Elasmosoma is a small genus comprising 13 described species globally, two of which are recorded in China. Given the limitations of existing faunistic surveys, it is inferred that a substantial number of species within these groups likely remain undiscovered in China, particularly in its north-western regions. This study reports first records of two parasitoid wasp genera Aphaereta and Elasmosoma in the Xinjiang Region of China. Specimens were collected in 2024 using Malaise traps in apple, apricot and pear orchards in the Aksu Prefecture. Amongst these, Aphaereta debilitata and subgenus Atopandrium are recorded from China for the first time.