No. 011 · spider · Risk: Moderate
Black Widow
Latrodectus mactans
In season · SeptemberSouthwestSoutheastMidwest / PlainsPacific West
- Field tell
- Glossy black body with a red hourglass on the underside; webs in woodpiles, sheds, and undisturbed corners.
- Why it matters
- Neurotoxic venom can cause muscle cramping and pain; rarely fatal to healthy adults.
- Season
- Most active spring through fall; can persist indoors or in sheltered structures year-round.
SPIDER BITE
If you're bitten by a spider
- Wash the bite with soap and water.
- Apply a cold compress to reduce pain and swelling.
- Try to safely note or photograph the spider without handling it.
- Seek medical attention, especially for black widow or brown recluse bites, or if symptoms spread beyond the bite site.
Not medical advice. Call 911 or Poison Control 1-800-222-1222.
Related spiders
- Brown Recluse — Dull brown with a dark violin-shaped mark behind the head; hides in boxes, closets, and stacked firewood.