The Southern house spider is a species of large North American spider which exhibit strong sexual dimorphism. The males may be mistaken for brown recluses because the two have similar coloration and body structure. However, compared to the brown recluse, Southern house spiders are typically larger in size, lack the distinctive violin shape, and have unusually long slender pedipalps.

The females are dark brown or black and more compact. Both sexes may grow to be roughly 2 inches across (legs extended), with the males typically having longer legs, and the females often having larger, bulbous bodies. The abdomen of the southern house spider is covered with fine velvety hair.
Female Southern house spiders are rarely seen, as they build radial webs around crevices, for which reason their family (Filistatidae) is called “crevice weavers”. Females seldom move except to capture prey caught in their webs. Males, on the other hand, typically wander in search of insects to hunt and females to mate with. Southern house spiders are capable of crawling through crevices as narrow as 1/4 in due to their elongated bodies and compact legs.

The Southern house spider is a cribellate spider. That means its spinnerets do not produce adhesive webbing. Instead, to capture prey, the spider uses its legs to comb webbing across a spiked plate near the spinnerets. This combing action frays and tangles the strands, producing a fine, velcro-like netting that ensnares insects. The Southern house spider can be a particular pest during the Winter.

Male Southern house spiders sometimes appear aggressive, but they do not bite unless trapped and their mouthparts are too small to easily penetrate human skin. They do, however, have an unnerving tendency to crawl across anything in their path. This is not aggression; these spiders are simply nearly blind and cannot see larger obstacles – this includes animals or humans. If detected, these spiders instinctively play dead (a tactic which is effective against their common predators).