House spiders occur throughout the world and have derived their name from their presence inside human dwellings. A number of species are classified as house spiders, although the common house spider is the most recognized. These arachnids are also sometimes referred to as American house spiders. Female common house spiders measure 5 to 8 mm in length, while males measure only 4 mm. Common house spiders are typically brown or gray in color, with darker chevron markings along their bodies. A house spider’s body is divided into the cephalothorax and the abdomen. Like scorpions, mites and ticks, house spiders are wingless. They are classified as arachnids rather than insects and have eight, single-lens eyes.
House spider webs are irregularly shaped and can be located in various places within a home, including windows, ceiling corners and above or beneath fixtures.
Female common house spiders (Parasteatoda tepidariorum) deposit as many as 250 eggs into a sac of silk. These sacs are often brown in color and are flask-like in shape. Females produce up to 17 of these sacs during a lifetime, resulting in more than 4,000 eggs. Males are smaller than females, measuring only 4 mm in length as opposed to the female’s 8 mm. Unlike some other spider species, male and female common house spiders may choose to cohabitate and mate numerous times.