Almost everyone has encountered them: long-legged, pale spiders hanging in wispy cobwebs in garage corners, basement ceilings, and crawl spaces. Cellar spiders — commonly called daddy long legs — are among the most widespread indoor spiders in the United States. They’re completely harmless to humans, pose no threat to your home’s structure, and actually prey on other spiders and insects. But their habit of building increasingly messy webs in every corner of a basement or garage is what drives most homeowners to want them controlled.

Identification

Cellar spiders (family Pholcidae) have very small bodies — only about 1/4 inch long — with extremely long, thin legs that can give the spider an overall leg span of 1-2 inches. Body color is pale gray to tan. Their webs are irregular and three-dimensional rather than the symmetrical spiral webs of orb weavers. When disturbed, cellar spiders vibrate rapidly in their web — a defense mechanism that blurs their outline.

Note: “Daddy long legs” is also the common name for harvestmen (order Opiliones) — a different arachnid that has a compact oval body and no visible waist. True cellar spiders (Pholcus species) have a segmented body with a distinct waist, like other spiders. Both are harmless.

The Venom Myth

A persistent urban legend claims cellar spiders are the most venomous spiders in the world but can’t penetrate human skin. This is false on both counts. Cellar spider venom has not been shown to be highly toxic to humans, and their fangs are fully capable of penetrating skin — they simply never do, because they’re not interested in biting humans. This myth has been thoroughly debunked by researchers.

Why They Accumulate

Cellar spiders build webs and leave them in place indefinitely, adding to existing structure. Webs accumulate dust and debris over time. As their population grows, entire corners and ceiling edges of basements can become layered with old and new webs. They don’t clean up after themselves, and each new generation of spiders adds new webbing to existing sites.

Prevention and Control

  • Regular vacuuming of webs is the most immediate control — remove both webs and any egg sacs
  • Reduce moisture in basements and crawl spaces with dehumidifiers (drier conditions favor fewer spiders)
  • Seal gaps and cracks that allow them to enter from outside
  • Reduce exterior lighting to decrease insect populations they feed on
  • Residual insecticide applications to corners and ceiling edges are effective

Professional Treatment

If you’re dealing with heavy cellar spider populations in your basement or garage, professional treatment combined with web removal provides the fastest reset. Miller Pest Solutions handles spider control throughout Des Moines, Omaha, and Kansas City. A perimeter and interior treatment knocks down existing populations and provides residual protection. Call for a free phone bid: Omaha (402) 769-0997 | Des Moines (515) 329-8801 | Kansas City (816) 815-0498