Phlebotomus betisiwas described from Malaysia and classified after its description in the subgenusLarroussius. It was the only species to have a pharyngeal armature composed of dot-like teeth and an annealed spermatheca whose head is carried by a neck in females. Males were characterized by having a style bearing five spines and a simple paramere. The study of sandflies originating from a cave in Laos enabled us to discover and describe two sympatric species close toPh. betisiLewis & Wharton, 1963 and new for Science:Ph. breyiVongphayloth & Depaquit n. sp., andPh. sinxayaramiVongphayloth & Depaquit n. sp. They were characterized morphologically, morphometrically, geomorphometrically, molecularly, and proteomically (MALDI-TOF). All approaches converged to validate the individualization of these species whose morphological differential characters lay in the two genders by the observation of the interocular suture and by the length of the last two segments of the maxillary palps. In males, the length of the genital filaments discriminates these species. Females are distinguished by the length of the ducts of the spermathecae as well as by the narrow or enlarged shape of the neck bearing their head. Lastly, the particular position of the spines of the gonostyle coupled with molecular phylogeny led us to remove these three species from the subgenusLarroussiusNizulescu, 1931 and to classify them in a new subgenus:LewisiusDepaquit & Vongphayloth n. subg.