Slender-legged Sac Spiders

Cheiracanthiidae C.L. Koch, 1839

Type genus: Cheiracanthium

The Cheiracanthiidae include pale ground living spiders with comparatively thin legs and can be confused with the Clubionidae (where its genera were previously placed). At least males in the genera Cheiracanthium and Eutittha have a distinct spine-like extension at the base of the cymbium of the male pedipalp. The more scientific diagnosis is (after Ramirez 2014; as Eutichuridae):  Retrolateral tibial apophysis present, two claws, and claw tuft. They differ from other dionychans by having the anterior lateral spinnerets conical and contiguous, not sexually dimorphic, posterior median spinnerets conical, cylindrical gland spigots small, similar to aciniforms or absent, posterior lateral spinnerets with distal article usually elongate, eye group wide, spanning the entire width of the caput, lateral eyes placed together on raised tubercles, usually without thoracic fovea, without thick, curved setae on the anterior dorsal abdomen. The tapetum of the indirect eyes has a median band of dark holes, instead of a definite dark line. Some species of Cheiracanthium and Eutittha may have a shallow thoracic fovea and a canoe tapetum, but have a posteriorly extending retrolateral margin of the cymbium as in several other eutichurids.