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As treated by Platnick (2013), the spider family Dictynidae includes 575 species, including some ecribellate genera formerly placed in Agelenidae; according to Bradley (2013), 290 species are found in North America north of Mexico (Bradley notes that nearly half of these species belong to the closely related genera Dictyna, Emblyna, Mallos, and Mexitlia, the males of which generally have distinctively bowed cheliceral bases).
Dictynids typically have eight eyes in two transverse rows, usually with the anterior median eyes reduced; some species lack the anterior median eyes altogether and others (such as troglobites) lack eyes entirely. Dictynidae has a worldwide distribution with the great majority of species occurring in the northern hemisphere, especially in the Holarctic region. In North America, numerous endemic species are known from Texas (mainly troglobites) and the Pacific Coast region. All ecribellate dictynids are found at or below ground level. A number of ecribellate dictynids are specialized troglobites, but most species are forest inhabitants living deep in leaf litter or under bark, logs, rocks, and other objects. Their webs are usually very reduced sheets and function mainly as retreats. Cribellate dictynids occur in a wider range of habitats, ranging from deep leaf litter to branch tips high in the canopy of old growth conifers. Many genera in the entirely cribellate subfamily Dictyninae are arboreal, constructing webs on foliage, flowers, branches, and dried plant stalks. With experience, an observer can learn to distinguish the webs of most dictynids from those of cobweb weavers (Theridiidae) and hackledmesh weavers (Amaurobiidae). The webs of theridiids have a more open structure with unadorned silk lines, lacking the cribellate zigzags; in contrast to the space-filling webs of most theridiids, dictynid webs are often constructed in the open without overhanging protection. Amaurobiids are larger spiders and build a spacious web, often with a funnel-like depression leading to a tubular retreat. Some dictynids do not build obvious webs (e.g., in the ecribellate genera Blabomma, Cicurina, and Yorima) and instead are either free-ranging spiders found near the ground or build inconspicuous webs under logs or other debris. (Bradley 2013)
Bennett (2005) reviewed in some detail the complex history of the systematics and taxonomy of the family Dictynidae. Bennett notes that many unanswered questions about the delineation of this family remain to be addressed and that most genera require revision.