Abstract
The genus Hylomus Cook & Loomis, 1924 is reviewed from Vietnam, with 13 recorded species. Of these, three are described as new, H. songoku sp. nov. from Xuan Son National Park, H. namek sp. nov. from Cuc Phuong National Park, and H. saiyans sp. nov. from Vinh Phuc and Ha Giang Provinces. The new species, H. songoku sp. nov., is distinguished by gonopod solenophore with rounded lobuliform lamina medialis, and well-developed lamina lateralis with a densely setose area; tip of gonopod tuberculiform. H. namek sp. nov. is separated from its congeners by its gonopod femorite being short, parallel-sided, slightly constricted at the middle; tip of gonopod rounded; and lastly, H. saiyans sp. nov. is diagnosable by its gonopod femorite being long and enlarged distally, postfemoral region short, tip bilobuled. The relationship among Hylomus species from Vietnam was analyzed using a fragment of the 16S rRNA mitochondrial gene. The analysis supports the monophyly of the genus Hylomus. It is recommended that more Hylomus species be added in the analysis to better clarify the phylogenetic relationships in the genus.