Rhodnius Stål, 1859 is the second largest genus of Triatominae after Triatoma Laporte, 1832, and includes several important Chagas vectors. Genitalia in Reduviidae are frequently used for species identification, but the current use of terminology for it is inconsistent in Triatominae. Here, Rhodnius micki sp. nov., is described from Bolivia and considered as belonging to the pictipes group based on its morphological char acters and distribution. Detailed documentation of the genitalia of Rhodnius micki sp. nov. is provided with emphasis on its everted phallus, especially the endosomal sclerites, which are potentially useful as species-level diagnostic features in Rhodnius. To further verify the validity of this species, the head shapes and wing venation patterns of five species in Rhodnius are compared with morphometric analysis. After reviewing taxonomic and comparative morphology papers of assassin bugs, a vocabulary with a terminol ogy of morphological characters, especially of external male genitalic characters, is assembled with the preferred terms and the synonyms listed. Establishing a consistent terminological framework will greatly facilitate future research on the homology of these structures across Triatominae and will ultimately con tribute to our understanding of the evolution of these groups.