Cellar spiders (family Pholcidae), commonly called 'daddy long-legs spiders,' are small-bodied spiders with extremely long, thin legs. The most common indoor species in Arizona is Pholcus phalangioides, with a body length of about 1/4 inch and legs up to 2 inches long. Cellar spiders build loose, irregular webs in corners of rooms, basements, garages, and undisturbed indoor spaces. They are completely harmless to humans — the myth that they are 'the most venomous spider in the world' is false; their venom is mild and their mouthparts are capable of biting humans, though bites are extremely rare. Cellar spiders are actually beneficial: they are known to invade and consume other spiders, including black widows, in their webs. When disturbed, they vibrate rapidly in their web as a defense mechanism.
👁Warning Signs
Long-legged spiders in loose, irregular webs in corners of rooms, garages, or basements. Vibrating rapidly when disturbed. Accumulation of old webs and prey remains in undisturbed corners.
⚠Health & Property Risks
Not medically significant. Completely harmless to humans. Beneficial predators of other spiders and insects.
Prevention Tips
Regular vacuuming of corners and undisturbed areas removes webs and spiders. Reduce insect populations that serve as prey.
🛡Professional Treatment
Web removal by vacuuming. No chemical treatment necessary.
Frequently Asked Questions — Cellar Spider
The Cellar Spider (Pholcus phalangioides) is pale gray to tan with darker markings on the abdomen and typically measures Body: ~1/4 inch; legs: up to 2 inches. Cellar spiders (family Pholcidae), commonly called 'daddy long-legs spiders,' are small-bodied spiders with extremely long, thin legs. The most common indoor species in Arizona is Pholcus phalangioide.
The Cellar Spider is generally low-risk, but caution is still advised. Not medically significant. Completely harmless to humans. Beneficial predators of other spiders and insects.
In Arizona, cellar spiders are most often encountered in the following situations: Long-legged spiders in loose, irregular webs in corners of rooms, garages, or basements. Vibrating rapidly when disturbed. Accumulation of old webs and prey remains in undisturbed corners.
The Cellar Spider is most active during: Year-round indoors. Arizona's warm desert climate can extend activity periods compared to other states, so year-round vigilance is recommended in the Phoenix metro and surrounding areas.
Regular vacuuming of corners and undisturbed areas removes webs and spiders. Reduce insect populations that serve as prey.
Web removal by vacuuming. No chemical treatment necessary.
If you spot a Cellar Spider indoors, avoid handling it directly. Capture it under a glass if possible for identification, or photograph it for reference. Contact Pest Control Bros for a professional inspection — we can confirm the species, assess the severity of the infestation, and recommend targeted treatment.
Dealing with Cellar Spider?
Pest Control Bros LLC serves Maricopa, Chandler, Casa Grande, Tempe, Gilbert, and Mesa. No contracts. Free inspections. Same-week service.
Related Articles — Cellar Spider
Wolf Spiders in Arizona: Identification, Bites, and How to Get Rid of Them
9 min read · Spiders
Black Widow Spiders in Arizona: How to Identify, Avoid, and Remove Them
7 min read · Spiders
Spider Control in Maricopa, AZ: Black Widows, Brown Recluse & Wolf Spiders
7 min read · Spiders
Black Widow vs Brown Widow Spider: Arizona ID Guide
10 min read · Spiders