Identification with medical caution
Black widow look-alikes
Most dark cobweb spiders in US buildings are not black widows. False identification drives panic spraying and missed meter boxes. This page compares look-alikes. For bites and removal, use the Black widow page. If someone is bitten, Poison Control or emergency care first.
True widows in the United States
Latrodectus females are often shiny black with a red hourglass on the underside. Western, southern, and northern species vary. Brown widows (Latrodectus geometricus) are mottled brown with an orange hourglass and have spread in the South; still a widow, still not a toy. Males are smaller. Irregular cobwebs in clutter, not orb webs, not wolf-spider hunters on the floor.
False widow, brown widow, house spider
| Black widow | Brown widow | Common cobweb house spider | Cellar spider | |
|---|---|---|---|---|
| Look | Shiny black; red hourglass underneath | Mottled brown; orange hourglass | Brown bulbous abdomen, no hourglass | Tiny body, very long legs, bounces in web |
| Web | Irregular cobweb in a protected box | Cobweb, often with spiky egg sacs | Corner cobwebs in rooms | Messy basement ceiling corner |
| Medical | Latrodectus — clinician | Latrodectus — still medical if bitten | Generally incidental | Negligible; venom meme is false |
| First move if unsure | Do not handle. Photo. Open species page | Same | Optional vacuum | Optional vacuum |
Common house spider and Cellar spider are the usual indoor mix-ups. Wolf spider is a ground hunter, not a cobweb waiter. Brown recluse is a different medical spider with a range map people ignore.
Medical caution
Do not apply folklore tourniquets. US Poison Control 1-800-222-1222. Photograph the spider if it is safe. Do not ride the bus with a live widow in a jar. Control of an unbitten home is gloves, clutter, and vacuum — details on the species page.
Species pages
Each species article has the control sequence and safety notes. This page only splits look-alikes.
Black widow
Latrodectus spp.
Widow spiders are the medically important cobweb spiders of US clutter: woodpiles, meter boxes, playgrounds…
Common house spider
Parasteatoda tepidariorum and similar cobweb spiders
The common house spider builds messy cobwebs in corners and eats other insects. It is not a widow (no…
Common questions
Should I kill every dark spider?
No. Learn the hourglass and the web. Indiscriminate spraying misses the meter box and kills hunters you wanted.
Is a false widow as dangerous as a black widow?
Steatoda “false widows” are not Latrodectus. Bites are usually minor. Still do not handle spiders you cannot ID, and still get care for a bad reaction.