Their chelicerae are of normal proportions, but the pedipalps are very elongated and thin in some groups.

The subfamily Ortholasmatinae occur on both sides of the Pacific Ocean: in western North America from Alaska and British Columbia to Mexico and possibly Honduras, but also eastern Asia (China, Japan Thailand and Vietnam).

The subfamily Nemastomatinae occur across Europe and near, including Iceland and the Caucasus, plus in the Atlas Mountains of North Africa, from Anatolia to northern Iran.

Most species are geographically restricted to small zones in mountainous regions.

[1] The genus name Nemastoma is a combination of Ancient Greek nema "thread" and stoma "mouth", referring to the elongated pedipalps.