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The spider family Corinnidae (antmimic spiders) includes around 1083 species (Platnick 2013). In North America north of Mexico there are around 127 species, including several introduced species, with most of the diversity found in the southern portion of this region (Ubick and Richman 2005; Bradley 2013). Corinnids are generally ground dwellers and are commonly found beneath rocks and in leaf litter. Members of the genus Trachelas also occur on foliage and some species frequently enter houses, where they may be of minor medical concern (Platnick and Shadab 1974). The convergent cone-shaped spinnerets of corinnids distinguish them from ground spiders of the family Gnaphosidae, which have conspicuous cylindrical spinnerets that are often visible from above. Like most spiders, corinnids have eight eyes.
Although often brown, some corinnids are colorful. Ant mimicry is common in this family (and at least some species seem to be closely associated with ants) and some species are believed to be mimics of mutillid wasps. Although most corinnids are nocturnal, the ant mimics (as would be expected) tend to be diurnal. As is common for the families of two-clawed hunting spiders (dionychans), corinnids build sac-like retreats, often under rocks or other debris on the ground. The egg sacs, which are typically flat discs, may be deposited in the retreats or attached to the substrate (Comstock  includes a photograph of egg cases of Castianeira descripta on the underside of a stone). Historically, corinnids were included in a family Clubionidae that was defined far more broadly than it is today.
(Ubick and Richman 2005; Bradley 2013)