Broad-faced Sac Spider
Trachelas minor
Trachelidae, Order Araneae
Physical Description
Compact and robust body with a distinctively smooth, dark reddish-brown to orange cephalothorax and a pale yellowish-gray or tan oval abdomen.
Size Estimate
Body length typically ranges from 5 to 10 millimeters, with a modest leg span proportionate to its compact build.
Coloration & Markings
Dark reddish-brown to deep mahogany head region contrasting sharply with a plain, light tan or grayish abdomen lacking prominent patterns.
Web Type
Does not build a traditional web for trapping prey; instead, constructs a dense silken retreat or sac in which it rests during daylight hours.
Eye Arrangement
Eight small eyes arranged in two closely spaced, slightly recurved rows typical of the family.
Leg Characteristics
Banded or uniform reddish-brown legs that are relatively stout, with the first pair slightly modified for handling prey.
Venom & Safety Information
Venom Information
Mildly cytotoxic venom used primarily to subdue small invertebrate prey, with minimal potency against humans.
Medical Significance
Not medically significant. A bite may cause minor, temporary local pain, redness, or swelling comparable to a mild bee sting.
Safety Recommendations
Keep living areas clear of clutter, shake out shoes before wearing, and gently relocate wandering individuals outdoors using a cup and paper.
Habitat & Behavior
Habitat & Range
Widely distributed across North America, commonly found in leaf litter, under stones, bark, and frequently wandering into residential homes.
Behavior & Temperament
Nocturnal hunter that actively forages for prey at night and hides in a silken sac by day. Generally docile unless trapped or cornered.
Diet & Prey
Feeds primarily on small insects and other wandering spiders using active stalking and ambush techniques.
Seasonal Activity
Most active during the warmer spring and summer months, often seeking indoor shelter as temperatures drop in autumn.
Description
The Broad-faced Sac Spider is a common yet fascinating nocturnal visitor to homes and gardens, easily recognized by its shiny, dark head and pale abdomen.
Key Features
Glossy, dark reddish-brown cephalothorax contrasting against a lighter, patternless oval abdomen.
Similar Species
Other sac spiders such as Cheiracanthium species, which are typically paler greenish-yellow rather than dark-headed.
Life Cycle
Females produce silken egg sacs hidden in protected areas, guarding them until the spiderlings hatch and disperse.
Ecological Importance
Acts as an effective natural predator that helps control populations of small household and garden insects.
Conservation Status
Secure and widespread, with stable populations globally.
Interesting Facts
Despite being frequent indoor guests, they prefer outdoor habitats and only enter buildings accidentally while wandering.
Photography Tips
Use macro lenses with good side-lighting to highlight the smooth texture and dark coloration of the cephalothorax against a neutral background.
Identified: 2026-08-25T01:24:59.186285