The spider family Mysmenidae (dwarf cobweb weavers) includes 130 described species (Platnick 2013). The family is primarily tropical (Bradley 2013), but a half dozen species are known from North America north of Mexico (Lopardo and Coddington 2005).
Mysmenids are tiny spiders that live near the ground, typically in leaf litter and similar microhabitats in very humid areas. Mysmenid webs are unusual among orb-weaving spiders in their pronounced three-dimensionality. Rather than spin radial lines in the same plane as the orb, so much of the web is out of this plane that it resembles a space filling web like that of a theridiid. At least in Mysmena, the out-of-plane radii are left over from exploration of the web site; these exploratory lines would normally be removed by most orbweavers (Lopardo and Coddington 2005). Some mysmenids apparently do not build their own webs at all (some have even lost the ability to produce the sticky silk characteristic of orbweavers), instead stealing prey from the webs of other spiders. Lopardo and Coddington (2005) should be consulted for details, including illustrations, about web construction by various mysmenid genera and species. Like so many other spiders, mysmenids have eight eyes arranged in two rows, but in many (all?) species the eyes are white, except for the dark anterior median eyes.
Lopardo and Coddington (2005) report on known habitat associations for some North American species, although they note that this family has been poorly collected. These authors also review the rather tangled taxonomic history of this group.