Understanding the
Indoor Sac Spider

This page provides information about the House Sac Spider (also known as the Indoor Sac Spider and the Broad Faced Sac Spider), a common spider found in homes across Bucks County, Pennsylvania, the United States, and other parts of the world.

A typical House Sac Spider (Trachelas tranquillus).

Appearance

The House Sac Spider, scientifically known as Trachelas tranquillus, is typically a pale yellow or beige color. They have a relatively broad cephalothorax (the fused head and thorax) compared to some other sac spiders. Their legs are usually lighter in color and can appear somewhat translucent. They are generally small to medium in size, with a body length ranging from approximately 0.2 to 0.4 inches (5 to 10 millimeters).

Habitat and Behavior

As their common names suggest, House Sac Spiders are frequently found indoors. They don't build traditional webs for catching prey. Instead, they are active hunters, typically foraging at night. During the day, they often retreat into silken sacs or retreats, which they construct in crevices, under furniture, behind pictures, or along baseboards. They are known for their relatively quick movements.

Bite and Potential Concerns

Like most spiders, the House Sac Spider can bite if threatened or pressed against the skin. While they possess venom, their bites are generally not considered medically significant to humans. Symptoms, if any, are usually mild and localized, such as slight pain, redness, or itching at the bite site. Serious reactions are rare.

Identification Tips

Look for a small to medium-sized spider with a pale yellow or beige body.
Observe their relatively broad front body section (cephalothorax).
They are often seen running quickly across walls or ceilings.
Finding small, silken sacs in corners or crevices can also indicate their presence.

Related Arachnids

HOW TO TREAT FOR SPIDERS

Spider treatment involves the detection and elimination of all webs. If this is not done, the spiders are likely to re-infest the structure. Generally, it is not possible to completely eliminate spiders with do-it-yourself products. As such, successful spider eradication should be left for a pest control professional who has the tools and experience to get the job done safely and effectively.

At Newtown Termite & Pest Control, Inc., we don't take your spider problems lightly. That's why we use a multifaceted process including the treatment of wall voids, attics, and cracks and crevices throughout the premise with gels, dusts, and other specialized products.

Schedule a FREE inspection today.