[2] The family includes 137 species divided between 20 genera.

[3] The cephalothorax of Theridiosomatidae includes one pair of labio-sternal glands which seems a characteristic of the family and could be considered as a variation of segmental glands opening on the base of prosomatic appendages in various Spiders.

This organ is composed of a cuticular sack-like reservoir opening on the sternum via a "pit", and of a cluster of functional units belonging to the class 3 of arthropodian epidermal glands.

Each unit includes a large adenocyte provided with characteristic foliaceous microvilli (heart-shaped in Naatlo) and numerous mitochondria, an excretory duct terminating to a pore (located on an "apophysis" in Wendilgarda) and canal cells.

Present in immature and both sexes, the labiosternal gland elaborates a golgian semiochemical, either a pheromone for intraspecific communication, or an allomone improving the prey capture.Labiosternal glands were discovered and named by André Lopez(1985,1988,1993)(external link :"archentoflor") As of April 2023[update], the World Spider Catalog accepts the following genera:[1]