Common House Spiders in Missouri: Identification Guide

Most spiders found in Missouri homes are completely harmless to people — and in fact are beneficial, eating the flies, gnats, and other insects that would otherwise be more numerous. The challenge for many homeowners is identifying which spiders warrant concern and which do not. Here is a guide to the most common spiders you are likely to encounter in and around your central Missouri home.

Cellar Spider (Daddy Longlegs)

The cellar spider (Pholcus phalangioides and related species) is one of the most common indoor spiders in Missouri. It has an extremely small body with very long, thin legs — the familiar "daddy longlegs" appearance (not to be confused with the harvestman, a non-spider arachnid also called daddy longlegs). Cellar spiders build loose, irregular webs in corners, basements, crawlspaces, and garages.

Hazard level: None. Cellar spiders are harmless, do not bite, and are actually beneficial as they catch and eat other spiders including brown recluses. The popular myth that they are the world's most venomous spider is completely false — they have tiny fangs that cannot penetrate human skin and their venom is not dangerous to humans.

Wolf Spider

Wolf spiders are large, hairy, and fast-moving — which makes them alarming to encounter, though they are harmless. Missouri wolf spiders (Hogna and related genera) can reach 25–35mm body length and are dark brown with patterned markings. They do not build webs but actively hunt prey on the ground, which means they are often found on floors, in garages, and in basements. Female wolf spiders famously carry egg sacs and then young spiderlings on their backs.

Hazard level: Very low. Wolf spiders can bite if provoked but are not aggressive and their bite typically causes only minor local pain — comparable to a bee sting in most cases.

American House Spider

The American house spider (Parasteatoda tepidariorum) is a small, brownish spider — about 4–8mm — that builds messy cobwebs in corners, window frames, and undisturbed areas throughout homes. It is the classic "cobweb spider." The abdomen has a somewhat mottled, irregular pattern.

Hazard level: None. American house spiders are harmless and one of the most beneficial spiders in Missouri homes, catching a variety of flying and crawling insects.

Orb Weaver Spiders

Orb weavers are the classic spiral-web builders seen in gardens and around exterior lighting. Missouri has numerous species; many are large and colorful — the garden orb weaver and black and yellow garden spider (Argiope aurantia) are commonly seen. They build large, circular webs outside, typically in vegetation, in corners of buildings, and near outdoor lights that attract insects.

Hazard level: None. Orb weavers are completely harmless to humans and highly beneficial in gardens and around buildings.

Jumping Spiders

Jumping spiders are small (5–18mm), compact, and hairy with large forward-facing eyes that give them an unusually alert appearance. They are active daytime hunters that stalk their prey rather than using webs. Missouri has many jumping spider species; they are often seen on sunny exterior walls, window frames, and vegetation.

Hazard level: None. Jumping spiders are curious but harmless. They may approach humans out of curiosity (their eyesight is remarkably good) but do not bite.

Grass Spider

Grass spiders (Agelenopsis species) build distinctive flat, funnel-shaped webs in grass, shrubs, and along building foundations. The spider waits at the narrow end of the funnel for prey to fall onto the web. They are medium-sized, brownish with two dark stripes on the cephalothorax.

Hazard level: None. Grass spiders are harmless and rarely enter homes.

When to Be Concerned

Of all common Missouri house spiders, only the brown recluse and black widow are medically significant. Learning to identify these two species — see our dedicated articles on brown recluse spiders and black widow spiders — is the most valuable spider identification skill for a Missouri homeowner. For everything else you are likely to encounter, the spider is almost certainly harmless and is earning its keep eating other insects.