Eresidae

Velvet spiders
male Eresus kollari
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Araneomorphae
Family:	Eresidae C. L. Koch, 1851
Genera
See text.
Diversity
9 genera, 97 species

See text.

The velvet spiders (family Eresidae) are a small group (about 100 species in 9 genera) of almost totally Old World spiders (exception: a few species are known from Brazil). The characteristics of this family of spiders are that they are entelegyne (have a genital plate in the female), eight-eyed araneomorph spiders that build unkempt webs. They are cribellate (use woolly silk). Some species are nearly eusocial, lacking only a specialized caste system and a queen. They cooperate in brood rearing, unlike most other spiders except for some African agelenid spiders in the genus Agelena and a few others.

Female velvet spiders exhibit a remarkable type maternal care unique among arachnids. Upon the birth of her brood, the mother spider liquefies her internal organs and regurgitates this material as food. Once her capability to liquefy her insides is exhausted, the young sense this and consume the mother.

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

As of October 2015^[update], the World Spider Catalog accepted the following genera:

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