They can be distinguished from most species except the Penestomidae by their semi-rectangular carapace and clypeal hood.

[citation needed] Female velvet spiders exhibit a remarkable type of maternal care unique among arachnids.

Upon the birth of her brood, the mother spider liquefies her internal organs and regurgitates this material as food.

[citation needed] The genus Penestomus was previously placed in Eresidae as the subfamily Penestominae, but was elevated to its own family, Penestomidae, in 2010.

[citation needed] As of April 2019[update], the World Spider Catalog accepts the following genera:[1]