Menu ☰
Be careful

False black widow

Steatoda grossa
Also called cupboard spider, dark comb-footed spider

Not a true widow: a bite can hurt and swell for a day or two, but it is far milder than a black widow bite.

False black widow, photo 1
Photo: kenkneidel, CC0, via iNaturalist
SizeAdult female body about 6–10.5 mm (1/4 to 3/8 inch); males smaller, about 3–5 mm (1/8 to 1/5 inch)
Where in the houseBathroom, kitchen, basement, garage, windows and walls, closets
WhenFound indoors year-round; adult females can live several years.

Check these features

  1. Shiny dark purplish-brown to nearly black, round to oval abdomen
  2. No red hourglass on the underside
  3. Often faint pale yellowish or grayish marks or a thin band on the top of the abdomen
  4. Reddish-brown front body and slightly darker legs
  5. Hangs upside down in an untidy cobweb in a corner, cupboard or under furniture

Bites and stings

Bites are uncommon and happen when the spider is trapped against skin. A bite usually causes burning or moderate pain within the first hour and local swelling or a small blister; some people feel mildly nauseous, headachy or tired for a day or two. Get medical care if symptoms spread or worsen, if the bite looks infected, or for signs of an allergic reaction such as trouble breathing or swelling of the face.

What to do

  1. Wash the bite with soap and water and apply a cool, damp cloth to ease pain and swelling.
  2. Watch the area over the next day; most bites settle on their own.
  3. Call 911 for trouble breathing or swelling of the face or throat.
  4. Get medical care if pain spreads, symptoms last more than a couple of days, or the area becomes red, hot and increasingly painful.
  5. If unsure whether it was a black widow, check the belly for a red hourglass in a photo, or trap the spider in a jar.

Look-alikes

Black widowsGlossy jet black with a red or orange hourglass on the belly; false black widows have no hourglass and are more brownish or purplish.
Noble false widow (Steatoda nobilis)Larger, with a cream, skull- or house-shaped pattern on the top of the abdomen; so far mainly in coastal California.
Common house spiderSmaller and paler, with a mottled tan-and-brown abdomen.

Why it came inside

This European spider thrives indoors and lives its whole life inside buildings, hunting insects and other spiders in quiet corners, cupboards and under appliances.

Keep it out

  • Vacuum webs and spiders from corners, under furniture and behind appliances.
  • Reduce clutter in closets, basements and garages.
  • Seal cracks and gaps around doors, windows and the foundation and fit door sweeps.
  • Place sticky traps along walls in basements, bathrooms and garages to catch wandering spiders.

What helps

Links go to Amazon search results so you can compare current options. As an Amazon Associate I earn from qualifying purchases. Always follow the product label.

Vacuum with a hose

Lets you remove bugs, webs and egg sacs without touching them. Empty the bag or canister outside right away.

See options on Amazon
Sticky traps

Flat glue traps set along walls and in corners show what is moving through and where. Place them where pets and children can't reach.

See options on Amazon
Door sweep

Closes the gap under an exterior door. If you can see daylight under the door, bugs can get in.

See options on Amazon
Caulk and sealant

Silicone or siliconized acrylic caulk closes cracks around windows, pipes and baseboards. Bigger gaps need foam backer rod or expanding foam first.

See options on Amazon
Weatherstripping

Seals the gaps around doors and windows that let in drafts and bugs alike.

See options on Amazon
Bug catcher

A long-handled catcher moves a spider or insect outside without you having to touch it.

See options on Amazon

Sources

  1. Penn State Extension
  2. University of California IPM
  3. Montana State University Extension

Checked October 18, 2026. Rating backed by 3 sources. How we rate danger.