The tube web spider (Segestria florentina) is a spectacular beast. Its body length can measure up to 22mm, making it one of the biggest spiders in the UK.
Its chelicerae (fanged mouthparts), often described as shining bottle green, are its most distinctive feature, and usually all that is visible when it is inside its hideaway, normally a hole in an old wall.
The long, radiating strands of its web act like trip wires, alerting the spider to passing prey. When it detects movement, it rushes out and pounces.
S. florentina is a very aggressive species and will bite violently at anything inserted into its tunnel retreat, including pencils, twigs and fingers.
There is no need to worry, though – this is a secretive and reclusive creature. It is uncommon and currently restricted to southern Britain, usually ports and market towns, and its venomous bite is said to be painful, but not dangerous.
Main image © Luis Miguel Bugallo Sánchez (Lmbuga Commons)(Lmbuga Galipedia), CC BY-SA 2.5 ES <https://creativecommons.org/licenses/by-sa/2.5/es/deed.en>, via Wikimedia Commons
