Hersiliidae
Two-Tailed Spider Identification Australia: Hersiliidae
Flat, bark-camouflaged hunter with two extremely long rear spinnerets, sprawling legs and rapid movement across Australian tree trunks.
Usually low riskTwo-tailed spiders are long-spinneret bark spiders in the family Hersiliidae. The apparent tails are not tails or stings: they are the greatly elongated rear spinnerets used to produce silk. A likely Australian identification combines those paired projections with a small, very flat grey-brown body, long sprawling legs and a tree-trunk or branch setting. These spiders do not sit in a large capture web. They camouflage against bark, leave fine silk lines over the surface and rush toward prey that contacts the silk. Photograph the rear of the abdomen and the whole spider on its substrate; a distant image of a flat brown spider is not enough for a family-level conclusion.
Quick identification
- Two extremely long posterior spinnerets projecting from the abdomen
- Flat grey or brown body patterned like bark or lichen
- Long sprawling legs, with the third pair noticeably shorter
- Very fast running over a tree trunk or branch when disturbed
- Fine guide threads on bark but no large prey-catching web
What to check next
Use a sharp rear or side photograph to prove that the two projections are spinnerets attached to the abdomen. Then confirm a flat bark-dwelling body and long uneven leg pairs; do not attempt a genus or species identification from colour alone.
When to seek medical help
Two-tailed spiders are not among the Australian spiders highlighted by healthdirect as medically dangerous. For a suspected bite, wash the area and use a wrapped cold pack for local discomfort. Seek medical advice if pain is severe, symptoms persist or worsen, swelling or itching increases, or you are worried. Call 000 for breathing difficulty, collapse or other signs of anaphylaxis.
Where it is usually seen
Tree trunks and branches, especially rough or patterned bark on eucalypts, in gardens, parks, woodland and forest. They may also be noticed on logs, fences or exterior walls close to trees, but Australian species are principally bark dwellers.