Bolas spiders have been treated as either the whole or part of either the tribe "Mastophoreae" or Mastophorini, the subfamily Mastophorinae, or the informal group mastophorines.

Bolas spiders are small nocturnal animals with conspicuous outgrowths on the upper (dorsal) surface of the cephalothorax.

The females of some bolas spiders (e.g. Mastophora cornigera) look remarkably like a bird dropping, thanks to their large, globular abdomen and brownish cephalothorax.

However, the Australian Ordgarius magnificus, which displays eye spots on its back that make it resemble the moth it hunts, ties leaves together with silk to form a retreat.

[9] Gertsch in 1955 also placed bolas spiders in the tribe Mastophoreae, again including Acantharachne (under the synonym Acantharanea).

showed that the species of the two bolas spider genera included in the study formed a strongly supported clade nested within Cyrtarachninae s.l.

[8] A wider study of the family Araneidae published in 2020 reached a similar conclusion, separating Cyrtarachninae s.l.

Some construct "spanning-thread webs", which have a small number of radii and widely spaced sticky threads that do not form spirals.

Bolas spiders do not spin webs at all, adult females catching their prey on single sticky threads.

Finally, some species capture their prey without a web, using their outstretched legs, as do juvenile and male bolas spiders.

However, the 2014 molecular phylogenetic study by Tanikawa et al. showed that this hypothesis did not fit with the evolutionary relationships they derived.

[13] Bolas spiders are found in America, Africa including Madagascar, and Australasia northwards into Asia.

In Pietermaritzburg, South Africa, adult females of Cladomelea akermani were observed with egg cases during July.

[6] Some male bolas spiders, such as those of Mastophora cornigera and Ordgarius magnificus, appear to be mature on emergence from their egg cases and so capable of inseminating females.

Adult female bolas spiders spend the day resting, disguised in various ways, including as bird droppings.

Cladomelea akermani whirls the bolas immediately after it has been prepared for about 15 minutes, even when there is no moth present.

This has not been observed to result in prey capture, but is remarkably similar to the midline of a Pasilobus web in which the spanning threads have been broken.

Juvenile females and males of all ages of M. hutchinsoni have a row of strong bristles on the prolateral surface of the tibiae and metatarsi of each of their first two pairs of legs which may aid in prey capture.

Moth flies of the genus Psychoda are prominent prey of juvenile and adult male Mastophora.

Their internal structure is complex, consisting of a mass of curled or folded fibre embedded in a viscid matrix which is in turn surrounded by a less viscous layer.

The folded thread inside the ball permits elastic elongations which extend the spider's striking range.

[17][16] Yeargan noted that records of natural enemies of bolas spiders all concern predators or parasitoids of the egg stage.