🕷️ Cellar Spider

Pholcus phalangioides · Araneae: Pholcidae

Cellar spiders build messy, irregular webs in corners and are one of the most commonly encountered spiders indoors. They're harmless, beneficial, and the 'deadly venom' myth about them is completely false.

SpiderCellar SpiderPholcidaeBeneficialDaddy Long LegsMyth
🕷️
Risk Level
Beneficial
📐 FIELD GUIDE ILLUSTRATION
Yellow Sac Spider (Cheiracanthium spp.) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

📐 FIELD GUIDE ILLUSTRATION
Spider Mite (Tetranychidae) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

📐 FIELD GUIDE ILLUSTRATION
Jumping Spider (Salticidae) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

📐 FIELD GUIDE ILLUSTRATION
Hobo Spider (Eudioptilus agrestis) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

📐 FIELD GUIDE ILLUSTRATION
Cellar Spider (Pholcidae) identification illustration with labeled anatomical features — PestControlBasics.com

Original illustration by PestControlBasics.com. Use anatomical labels above to confirm your identification.

🔬
PestControlBasics Editorial Team
Reviewed by Derek Giordano · Updated 2026

🔍 Identification

Adults: 8-10mm body; extremely long, thin legs (span of 70mm+); translucent grey-brown body; irregular, tangled web in corners. Confused with harvestmen ('daddy long legs'), which are not spiders. Cellar spiders are true spiders with 8 legs, two body segments, and produce silk. Harvestmen have one body segment and produce no silk.

🧬 Biology & Behavior

Cellar spiders are highly effective predators — they capture and kill prey much larger than themselves, including other spiders (including black widows in their range overlap). When disturbed, they vibrate rapidly in their web — this movement deters predators. They prey on flies, mosquitoes, and other insects caught in their webs.

⚠️ Damage & Health Risk

Messy, irregular webs in corners and ceiling junctions — the primary aesthetic concern. Zero damage, zero biting risk (their small chelicerae can't penetrate human skin in most cases). Actually beneficial by reducing other pest populations.

🔧 DIY Treatment

No treatment warranted. If web accumulations are the concern: vacuum down webs periodically. Reducing other insects (their prey) reduces cellar spider populations naturally.

👷 When to Call a Pro

Never warranted.

❓ FAQ

Is the 'daddy long legs is deadly' myth true?
Completely false. The myth claims cellar spiders have deadly venom but chelicerae too small to bite. In reality: cellar spiders can bite humans (their chelicerae ARE capable of piercing skin); the bite causes mild, brief discomfort; and their venom is not medically significant to humans. The myth is urban legend with no scientific basis.
Are cellar spiders the same as harvestmen?
No — harvestmen (opiliones) have one body segment, no silk glands, and are not spiders. Cellar spiders have two body segments, produce silk webs, and are true spiders. Both have very long legs, leading to the confusion.

🗺️ Geographic Range & Distribution

FactorDetails
U.S. RangeAll 50 states
Regional DetailBlack widow: nationwide. Brown recluse: South-Central states (not commonly found outside established range despite common misidentification). Wolf spider: nationwide.

📅 Treatment Timing Guide

Treating at the right time dramatically improves results. Pest control timed to the life cycle uses less product and achieves better long-term control.

PeriodAction
SpringInspection and perimeter treatment before pest season starts.
SummerActive monitoring and targeted treatments as needed.
FallPreventive treatment before overwintering pests seek entry.

💰 Professional Treatment Costs

Service TypeDIY CostProfessional Cost
Initial inspectionFree (self-inspect)$75–$150 (often credited to treatment)
One-time treatment$30–$100 in materials$150–$500
Annual service contractN/A$400–$900/year
Severe infestationOften ineffective alone$500–$2,500+

Prices vary by region, property size, and infestation severity.

❓ Common Questions About 🕷️ Cellar Spider

How do I confirm I actually have this pest (not something similar)?
The most reliable confirmation is a physical specimen — capture one and compare to reference images on this page. For cryptic pests (bed bugs, termites), look for secondary signs: frass, shed skins, mud tubes, or bites with a specific pattern. When uncertain, a professional inspection is faster than months of misidentification.
Can I treat this myself or do I need a professional?
DIY is effective for small, accessible infestations caught early. Professionals are worth the cost when: the infestation is inside wall voids or structural elements, multiple rooms are affected, you have health-risk pests (hantavirus, venomous species), or DIY has already failed twice.
How long until the infestation is completely gone?
Expect 3–8 weeks for most infestations with proper treatment. Insects with dormant life stages (pupae, eggs) extend the timeline because those stages are impervious to most insecticides. Follow-up treatments at 2 and 4 weeks catch each new cohort as they emerge.
What's the most common mistake people make treating this pest?
Treating only the visible pest population while ignoring the harborage site, entry point, or breeding location. Killing adults provides temporary relief but the population rebuilds from hidden egg cases, pupae, or new arrivals through unaddressed entry points.
📚 Sources: CDC Venomous Spiders · EPA Safe Pest Control
Published: Jan 1, 2025 · Updated: Apr 7, 2026

🗺️ US Distribution — Cellar Spider (Daddy Long Legs)

image/svg+xml
Common Occasional Not Present
States Present
49
Occasional
2
Primary Region
Continental US
📊 Source: University extension services, USDA, CDC vector data, and published entomological surveys.