In 1889, Westwood, in the Synopsis of the then known Mantidæ, prefixed to his Revisio insectorum familiæ Mantidorum, credits to North America, north of Mexico, nine species belonging to five genera,— Gonatista, Oligonyx, Thesprotia, Mantis, and Stagmomantis. several species were overlooked by him, and in reality up to the present time twenty-three nominal species have been at different times credited to this region and referred to ten genera,—Ameles, Empusa, Phasmomantis, Stagmatoptera, and Theoclytes, besides the foregoing. Several of the species, however, have been erroneously credited to this country, such as Empusa gongylodes and Mantis gemmata, both of which are East Indian. Several of the names, moreover, are synonyms of others, so that the number of species these references represent is speedily reduced more than one-half. All of these but Mantis Wheeleri Thom., Phasmomantis sumichrasti Sauss., and Oligonyx Uhleri Stal, I have seen, and to them can add several more not before recognized in the region in question, six of them being apparently hitherto undescribed, together with one genus. The total number of species is fifteen or sixteen, and of genera, eleven, only three of the genera—Litaneutria, Stagmomantis, and Oligonyx—having more than one species; undoubtedly more forms will be found in the West and South.