Microhexura is a genus of tiny North American spiders that was first described by C. R. Crosby & S. C. Bishop in 1925. It is the only genus in the family Microhexuridae. As of July 2020, it contained only two species, both found in the United States: M. idahoana and M. montivaga. M. montivaga occurs in the higher peaks of the Blue Ridge Mountains of North Carolina and Tennessee. M. idahoana occurs farther west, in the Cascades, the Blue Mountains, and the northern Rocky Mountains.
Scylaceus is a genus of North American sheet weavers that was first described by S. C. Bishop & C. R. Crosby in 1938. As of May 2019 it contains only two species, both found in Canada and the United States: S. pallidus and S. selma.
Sisyrbe is a monotypic genus of North American spiders in the family Linyphiidae containing the single species, Sisyrbe rustica. It was first described by S. C. Bishop and C. R. Crosby in 1938, and has only been found in the United States.
Ceratinopsidis is a monotypic genus of North American dwarf spiders containing the single species, Ceratinopsidis formosa. It was first described by S. C. Bishop & C. R. Crosby in 1930, and has only been found in United States.
Cheniseo is a genus of North American dwarf spiders that was first described by S. C. Bishop & C. R. Crosby in 1935.
Coreorgonal is a genus of North American dwarf spiders that was first described by S. C. Bishop & C. R. Crosby in 1935. As of May 2019 it contains only three species in the United States and Canada: C. bicornis, C. monoceros, and C. petulcus.
Epiceraticelus is a genus of North American dwarf spiders containing two species: Epiceraticelus fluvialis and Epiceraticelus mandyae. The first described species in the genus, E. fluvialis, was first described by C. R. Crosby & S. C. Bishop in 1931, and has only been found in the Midwestern and Eastern United States. The second species, E. mandyae, was described in 2019 by M. L. Draney et al. and occurs in the Southeastern United States from Eastern New Jersey south to Georgia and west to Louisiana. The male of E. mandyae has a curved proboscis that extends from below the eyes. Epiceraticelus mandyae was named after the late arachnologist, Amanda Howe, in honor of her contributions to the North American arachnology community.
Floricomus is a genus of North American dwarf spiders that was first described by C. R. Crosby & S. C. Bishop in 1925.
Gnathonaroides is a monotypic genus of North American dwarf spiders containing the single species, Gnathonaroides pedalis. It was first described by S. C. Bishop & C. R. Crosby in 1938, and has only been found in Canada and the United States.
Goneatara is a genus of North American dwarf spiders that was first described by S. C. Bishop & C. R. Crosby in 1935.
Paracornicularia is a monotypic genus of North American dwarf spiders containing the single species, Paracornicularia bicapillata. It was first described by C. R. Crosby & S. C. Bishop in 1931, and has only been found in the United States.
Pelecopsidis is a monotypic genus of North American dwarf spiders containing the single species, Pelecopsidis frontalis. It was first described by S. C. Bishop & C. R. Crosby in 1935, and has only been found in the United States.
Scirites is a genus of North American sheet weavers that was first described by S. C. Bishop & C. R. Crosby in 1938. As of May 2019 it contains only two species: S. finitimus and S. pectinatus.
Scironis is a genus of North American sheet weavers that was first described by S. C. Bishop & C. R. Crosby in 1938. As of May 2019 it contains only two species, both found in the United States: S. sima and S. tarsalis.
Scolopembolus is a monotypic genus of North American sheet weavers containing the single species, Scolopembolus littoralis. It was first described by S. C. Bishop & C. R. Crosby in 1938, and has only been found in the United States.
Scyletria is a monotypic genus of North American sheet weavers containing the single species, Scyletria inflata. It was first described by S. C. Bishop & C. R. Crosby in 1938, and has only been found in Canada and the United States.
Sisicus is a genus of sheet weavers that was first described by S. C. Bishop & C. R. Crosby in 1938. As of June 2019 it contains only three species, found in North America, Europe, Siberia, and East Asia: S. apertus, S. penifusifer, and S. volutasilex.
Sisis is a genus of North American sheet weavers that was first described by S. C. Bishop & C. R. Crosby in 1938. As of May 2019 it contains only two species, both found in Canada and the United States: S. plesius and S. rotundus.
Sitalcas is a monotypic genus of North American sheet weavers containing the single species, Sitalcas ruralis. It was first described by S. C. Bishop & C. R. Crosby in 1938, and has only been found in the United States.
Smodix is a monotypic genus of North American sheet weavers containing the single species, Smodix reticulata. It was first described by S. C. Bishop & C. R. Crosby in 1938, and has only been found in Canada and the United States.
