Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
Family Pholcidae, Order Araneae. Characterized by exceptionally long, delicate legs and a small, oval or cylindrical abdomen.
Physical Description
The spider features an extremely slender, delicate body with a pear-shaped cephalothorax and a long, cylindrical abdomen. Its proportions are dominated by its extraordinarily long, thread-like legs.
Size Estimate
Body length ranges from 7 to 10 millimeters, with a leg span stretching up to 5 to 7 centimeters.
Coloration & Markings
Pale, translucent yellowish-gray or whitish body, often featuring faint darker markings on the cephalothorax that can sometimes resemble the shape of a skull.
Web Type
Irregular, messy tangle webs built in dark, damp corners, cellars, basements, and ceilings.
Eye Arrangement
Eight eyes arranged in a unique grouping consisting of two triads on raised tubercles on the sides of the cephalothorax and a pair of smaller median eyes.
Leg Characteristics
Extremely long, thin, fragile legs with flexible joints that allow the spider to perform a vigorous spinning or bouncing motion when disturbed.
Venom & Safety Information
Venom Information
Contains mild venom used to subdue small insect prey via tiny chelicerae, completely ineffective and harmless to humans.
Medical Significance
Harmless to humans. Despite urban legends regarding extreme potency, they lack the anatomical capability to effectively puncture human skin.
Safety Recommendations
No safety measures needed as they are entirely harmless. If unwanted, gently relocate using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide, heavily synanthropic, commonly found indoors in corners of rooms, basements, cellars, and garages.
Behavior & Temperament
Docile and completely harmless to humans. When threatened, it violently shakes its web to blur its outline and confuse predators.
Diet & Prey
Insects and other spiders, famously including venomous spiders like widow spiders and hobo spiders, which it wraps in silk at a distance.
Seasonal Activity
Active year-round indoors due to climate-controlled environments, with increased mobility and mating activity observed during warmer months.
Description
Often mistaken for harvestmen, Pholcus phalangioides is a beneficial, long-legged household resident that quietly patrols corners, keeping pests and even dangerous spiders at bay.
Key Features
Extremely long and thin legs, pale translucent body, cylindrical abdomen, and the habit of vibrating rapidly in the web when disturbed.
Similar Species
Opiliones (Harvestmen, which are not true spiders and lack a divided body and silk glands) and Pholcidae family members like Holocus pluchei.
Life Cycle
Females carry eggs in a loose silk sac held in their mouthparts until hatching. Spiderlings undergo multiple molts to reach adulthood, living up to several years.
Ecological Importance
Acts as an effective natural pest control agent inside buildings by consuming household pests and other potentially dangerous arachnids.
Conservation Status
Not evaluated by the IUCN, thriving globally due to its close association with human habitations.
Interesting Facts
Despite an old wives' tale claiming they are the most venomous spiders with fangs too small to bite humans, this is entirely false; their venom is weak and they pose zero threat.
Photography Tips
Use macro lenses with gentle, diffused lighting in low-contrast indoor settings to capture the delicate leg structure and cephalothorax markings.
Identified: 2026-08-31T21:22:56.910137