Cellar Spider Identification — The Daddy Long Legs Spider
That pale, long-legged spider hanging upside down in a ceiling corner is almost certainly a cellar spider. Upload a photo and our free AI confirms it in seconds, or use the clues below.
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How to Identify Cellar Spider
Check these features before you rely on any single one — the combination is what confirms the ID.
Cellar spiders have thread-thin legs several times longer than the body, giving a leg span of 2 to 3 inches around a small body. No other common house spider has such long, delicate legs.
The body is about 1/4 to 3/8 inch, pale beige to grey and slightly see-through. The common long-bodied cellar spider has a cylinder-shaped abdomen; short-bodied cellar spiders have a small round one.
They build loose, irregular, tangled webs in ceiling corners, basements, garages, crawl spaces, and behind furniture, and hang upside down in them. Old webs collect dust into grey 'cobwebs'.
Touch the web and a cellar spider vibrates or whirls rapidly in place until it's a blur. This defensive 'whirling' is a giveaway behavior.
A grey spot on the front body section gives the common species its nickname, 'skull spider'. Up close you'll see eight eyes in two clusters of three plus a pair in the middle.
Like all spiders, cellar spiders have two distinct body sections and make silk. That separates them from harvestmen, the outdoor 'daddy long legs', which look like a single round body with no waist and make no webs.
Cellar Spiders and Other 'Daddy Long Legs'
Long-Bodied Cellar Spider
Pale, long-legged spider with a tube-shaped abdomen hanging in messy indoor webs. Harmless to people, and it eats other spiders, including black widows and hobo spiders.
Harvestman (Opiliones)
Also called daddy long legs, but not a spider: one fused, round body with no waist, two eyes, no silk, and no venom. Found outdoors on walls, plants, and tree trunks.
Crane Fly
A long-legged fly with two wings and six legs, often bumping around lights in spring and fall. Sometimes called 'mosquito hawk' or 'daddy long legs' in the UK. Harmless.
Marbled Cellar Spider
A cellar spider with a mottled brown-and-cream pattern, common in the southern US. Same behavior and same harmlessness as the pale species.
Brown Recluse
Also long-legged and brown, but its legs are much shorter and thicker, it has a violin marking, and it hides rather than hanging in open webs. Found mainly in the south-central US.
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Frequently Asked Questions
Sources & References
Our identification guides are researched from the authorities below and reviewed by the IdentifyThis team. AI photo identification is a helpful starting point — for anything involving safety (venomous species, edibility, or medical symptoms), always confirm with a qualified expert before acting.
- CDC — Pest- and health-related guidance
- American Arachnological Society — Spider biology & taxonomy
- BugGuide — Entomology identification community
- UC IPM — University of California Pest Notes
- Smithsonian — Insect & animal biology
Reviewed by the IdentifyThis team · Last updated August 2026