Abstract
The study is based on new material from the collections of the Naturalis Biodiversity Centre in Leiden (RNHM) and the Hungarian Natural History Museum (HNHM) and addresses issues in two genera: Epeus Peckham & Peckham, 1886 and Ptocasius Simon, 1885 from Thailand. Both genera are of Asian/Indomalayan origin, the latter with a diversity hotspot in the subtropical valleys of the Himalayas. Based on morphological data, we propose three new species of Epeus (Epeus daiqini sp. nov. (♂♀), Epeus pallidus sp. nov. (♀), Epeus szirakii sp. nov. (♀)) and two new species of Ptacasius (Ptocasius metzneri sp. nov. (♂♀) and Ptocasius sakaerat sp. nov. (♀)). Additionally, we redescribed E. tener (Simon, 1877) and added photographs of morphological characters. The genus Ptocasius is redefined due to the inclusion of 37 species, previously included in Yaginumaella Prószyński, 1979. Relationships and distribution of both genera are discussed in reference to molecular, morphological and distributional data, published by other authors in recent years.