Purseweb Spider Identification Guide

Key Visual Features

Purseweb spiders are burrowing relatives of tarantulas known for a very distinctive above-ground silk tube.

• Size: Body length roughly 12-25 mm, stout and heavily built.
• Color: Dark brown to black, sometimes with a slightly velvety sheen on the abdomen.
• Body shape: Robust, cylindrical abdomen and a wide, rounded cephalothorax typical of mygalomorph (tarantula-relative) spiders.
• Jaws (chelicerae): Large and oriented to strike downward rather than pincer-like, a feature shared with other primitive spider families.
• Eyes: Eight small eyes grouped closely together on a low mound at the front of the head.
• Legs: Eight short, thick legs adapted for digging rather than fast running.
• Silk tube: The best identification feature is not the spider itself but its structure — a sock-like, silk-and-debris tube that runs partly underground and partly up the base of a tree trunk or along the ground surface, often camouflaged with soil, moss, or bark bits woven into the silk.

Where and When You'd See It

Purseweb spiders live in wooded areas, often at the base of trees, embankments, or shaded slopes with stable soil. The silken tube is the most visible sign of their presence and can persist for a long time, sometimes for the life of the spider. The spiders themselves are rarely seen in the open since they spend virtually their entire lives inside the tube, only occasionally seen wandering (typically mature males searching for mates) during warm months.

Similar-Looking Bugs

• Trapdoor spiders: Also burrow, but build a hinged lid over a vertical burrow entrance rather than an external silk tube running up a trunk.
• Wolf spiders: Ground-dwelling but do not construct a tube retreat, and are more commonly seen moving in the open.
• Tarantulas: Related and similarly robust, but tarantulas typically dig an open burrow entrance without the camouflaged external sock-like extension.

Quick ID Checklist

• Look for the tube first: a camouflaged silk sock running up a tree base or along the ground
• Dark brown to black, stout, tarantula-like body
• Short, thick, digging-adapted legs
• Found at the base of trees or on shaded, stable slopes
• Spider itself rarely visible outside the tube except wandering males

Behavior Notes

The spider waits inside its silk tube and strikes at insects that walk across the outer surface, biting through the silk from within rather than emerging to hunt in the open, which makes the tube itself the most reliable clue to its presence.