Wood and Bright (1992) postulated that X. pfeilii is a synonym of X. volvulus, and this was further suggested by Gomez et al. (2018). Though appearing quite similar, the protibia of these species are different. That of X. pfeilii is distinctly triangular while that of X. volvulus is obliquely triangular. Analysis of COI and CAD sequences has also shown that these species are separate lineages (Cognato et al. in prep) and that X. pfeilii is a good species.