The following table made as simple as possible, and based almost exclusively upon the female sex, will serve to distinguish the species of Xiphidium hitherto described or recorded from the United States and Canada. It included only the species of Xiphidium proper; i. e., those of slender form with straight or nearly straight ovipositor, excluding the stouter species with distinctly arcuate ovipositor, commonly referred to Orchelimum, though both are classed together by Redtenbacher.