About Amaurobius fenestralis (Ström, 1768)
Amaurobius fenestralis is a species of spider that belongs to the family Amaurobiidae. It is one of at least two common house spiders that are referred to as lace-webbed spiders; the other is Amaurobius similis. The specific epithet "similis" for A. similis was chosen because of this species' similarity to A. fenestralis. Both species are often found near windows, which is the origin of A. fenestralis' specific name. The two species are hard to tell apart: adult A. fenestralis are generally smaller and lighter in color. Both species have V-shaped markings on their abdomens. A. fenestralis usually has two or three of these markings, while A. similis typically has four. Precise identification may require examination of the spider's genitalia. In areas around the United Kingdom, A. fenestralis has been observed preying on another spider species, Steatoda nobilis.
