Key to species of genus Malayepipona Modified from the key by Nguyen & Carpenter (2003). The characters are applicable to both sexes unless the sex is specified. 1. Metasomal sternum II strongly convex at basal half............... ................................................. M. assamensis Giordani Soika – Metasomal sternum II nearly flat or slightly convex at base, then slightly and gradually convex toward its apical margin .................................................................................................2 2. Tergum II without apical lamella ...........................................3 – Tergum II with apical lamella ................................................5 3. Forewing without a dark spot at apex of marginal cell. Upper part of propodeum with a pair of relatively blunt teeth just behind metanotum .............. M. clypeata Nguyen & Carpenter – Forewing with a dark spot at apex of marginal cell. Upper part of propodeum normal, without a pair of teeth just behind metanotum ...............................................................................4 4. Punctures on head and thorax large and coarse, border between punctures raised to form reticulation. Pronotal carina strongly produced at humeral angles. Metasomal terga dull, tergum I in dorsal view more than twice as wide as long, tergum II with strong and dense punctures .................. M. fincta, new species – Punctures on head and thorax smaller and weaker, border between punctures not raised. Pronotal carina not produced at humeral angles, round. Metasomal terga shiny, tergum I in dorsal view less than 1.5 times as wide as long, tergum II with weaker and sparser punctures ...... M. pagdeni Giordani Soika 5. Tergum II with short apical lamella, terga III–V without apical lamella .....................................................................................6 – Tergum II with longer apical lamella, tergum III with short apical lamella (lamella of tergum IV absent in M. seomyty) .. .................................................................................................7 6. Female head with long and dense hairs. Mandible with short teeth. Female clypeus almost yellow, with a medium longitudinal strip and sides black .......................... M. visenda Gusenleitner – Female head with shorter hairs. Mandible with prominent long teeth. Female clypeus entirely black ........................................ ............................................................ M. bidoup, new species 7. Metasomal tergum I about twice as wide as long in dorsal view; border between anterior and dorsal surfaces slightly raised with faint edge. Female clypeus black with two thick longitudinal yellow strips at lateral sides M. seomyty Nguyen & Carpenter – Metasomal tergum I less than twice as wide as long in dorsal view; border between anterior and dorsal surfaces bluntly angulate. Female clypeus entirely black or with two small yellow spots at base ................................................................8 8. Female clypeus with apical margin deeply emarginate medially, forming a sharp tooth on each lateral side. Mandible with prominent long teeth, inner side long with round edge. Female clypeus entirely black.............. M. furva Nguyen & Carpenter – Female clypeus with apical margin shallowly emarginate medially, forming blunt tooth on each lateral side. Mandibular teeth short with inner side quite short and slightly curved. Female clypeus black with two yellow spots at base.............. ....................................................... M. malickyi (Gusenleitner)

Published as part of Lien, Nguyen Thi Phuong, 2020, Two new species of the genus Malayepipona Giordani Soika (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with updated key to all recognised species, pp. 112-117 in Raffles Bulletin of Zoology 68 on page 117, DOI: 10.26107/RBZ-2020-0012, http://zenodo.org/record/4577195