Based largely on 668 one-hour samples collected during a survey of spiders in 16 major habitats of the Great Smoky Mountains National Park, habitat distributions, life history patterns, and other natural history traits are described for 14 species in the related theridiid genera Theridion, Rugathodes, and Wamba. Two to eight of these species were found in each of the 16 habitats. Among-habitat differences in the kinds and relative abundance of these species suggest that they may be good predictors of habitat. Richness, diversity, and evenness of this species assemblage are highest in middle to low elevation habitats. Rugathodes aurantius and R. sexpunctatus, two boreal sister species, are abundant in the highest elevation habitats, but differ sharply in microhabitat and habitat preference. Theridion frondeum is much more common in high elevation habitats than is its sister species, T. albidum, which is virtually limited to middle and low elevation habitats. Theridion lyricum is most common in dry, pine-dominated forests. The three most common species (R. aurantius, R. sexpunctatus, and T. frondeum) have a simple annual life cycle of five or six instars and similar phenologies: they mate during late spring (R. aurantius and R. sexpunctatus) and early summer (T. frondeum) and over-winter in antepenultimate and/or penultimate instars. Female-biased sex ratios were observed in juvenile cohorts of these species. Rugathodes aurantius, its natural history previously unknown, places its webs on the undersides of broad-leafed herbs close to the ground and captures small flying insects. Adult females engineer partly folded leaf retreats, carry the egg sac when disturbed, help their instar II spiderlings exit the egg sac, and then share the retreat with these spiderlings for at least a few days. Rapid early development (about two weeks from oviposition to emergence from the egg sac), the presence of females with egg sacs throughout the summer, and smaller clutch sizes in late summer suggest that a typical R. aurantius female produces more than one clutch.