Three new species of Stenomesius Westwood (Hymenoptera, Eulophidae) from China, with a key to Chinese species Author Fan, Jun-Jie School of Forestry, Northeast Forestry University, Harbin, 150040, China Author Li, Cheng-De School of Forestry, Northeast Forestry University, Harbin, 150040, China lichengde0608@sina.com text ZooKeys 2021 2021-10-12 1062 1 10 http://dx.doi.org/10.3897/zookeys.1062.67487 journal article http://dx.doi.org/10.3897/zookeys.1062.67487 1313-2970-1062-1 B8C0C3C49A944801AC4E0BF2C4923613 16E2FDB1C02D553B933B5608AFC08730 Stenomesius Westwood, 1833 Stenomesius Westwood, 1833: 343. Type species: Stenomesius pulchellus Westwood, by subsequent designation of Westwood 1839: 73. Euryscotolinx Girault, 1913: 266. Type species: Euryscotolinx guttativertex Girault, by original designation and monotypy. [Synonymised with Stenomesius Westwood by Boucek 1977 : 401]. Stenelachistus Masi, 1917: 201. Type species: Stenelachistus impressus Masi, by subsequent designation of Gahan and Fagan 1923 : 136. [Synonymised with Stenomesius Westwood by Boucek , 1977: 401]. Nioro Risbec, 1951: 25. Type species: Nioro elegantula Risbec, by monotypy. [Synonymised with Stenomesius Westwood by Boucek 1977 : 401]. Diagnosis. The genus can be easily distinguished from other eulophine genera by the following combination of characters: female funicle 4-segmented and club 2-3-segmented; mandible developed; pronotum without transverse carina; scutellum with sublateral grooves; propodeum medially with a strong X- or H-shaped carinae; hind tibial spurs normal; petiole shorter than hind coxa, gaster usually elongate. The genus Stenomesius is close to the genus Stenopetius Boucek and Euplectromorpha Girault in having similar type of propodeum with H- or X-shaped carinae, but it differs from Stenopetius Boucek in having: 1) female funicle 4-segmented (5-segmented in Stenopetius Boucek ); 2) pronotum without transverse carina (with distinct transverse carina in Stenopetius Boucek ); 3) petiole shorter than hind coxa (longer than hind coxa in Stenopetius Boucek ). It differs from Euplectromorpha in having hind tibia normal, at least with one spur distinctly longer than first hind tarsal segment in Euplectromorpha .