Yellow sac spider identification (Cheiracanthium inclusum)


Insect identifier · Spiders and scorpions

How to identify a Yellow sac spider

Cheiracanthium inclusum
· Also called sac spider, yellow house spider, yellow spider in house, sac spider bite

Yellow sac spider identification photo

Pale wandering spiders in ceiling corners get blamed for mystery night bites. Yellow sac spiders bite more often than recluses in much of the country, but the bite is usually a painful welt, not necrosis.

Pale wandering spider, silk sac in a ceiling corner, painful night welt. Leading mystery-bite spider in much of the country. No violin. Not a recluse. Immediate pain, then itch. Wash, ice, watch 48 hours. Do not cut a wound because the internet said recluse.

What does a yellow sac spider look like?

Pale yellow to greenish, darker jaws, no violin mark. Silken daytime sac in corners, not an orb web.

Yellow sac spider (Cheiracanthium inclusum) is Pale, 5–10 mm body. Colors people notice: yellow, cream, tan, green. Field marks: Pale yellow to greenish; Dark brown jaws contrast with pale body; No violin mark; Silken daytime sac in corners, not an orb web. It is found both. If those marks are missing, open Brown recluse, Yellow garden spider before you force this name. Search phrases that belong on this page include what a yellow sac spider looks like and yellow sac spider identification.

Identification marks

  • Pale yellow to greenish
  • Dark brown jaws contrast with pale body
  • No violin mark
  • Silken daytime sac in corners, not an orb web

Size: Pale, 5–10 mm body
Colors: yellow, cream, tan, green
Where: both

What a typical yellow sac spider bite looks like

Typical yellow sac spider bite or sting
A typical pattern. Reactions vary. This is a guide photo, not a diagnosis.

Painful immediately, like a bee sting, then a red welt that itches. Rarely a small blister. Wash, ice, watch for spreading infection.

People searching “yellow sac spider bite identification” want the pattern, not a single anonymous bump. Painful immediately, like a bee sting, then a red welt that itches. Rarely a small blister. Usually heals without medical drama. Immediate steps on this page: Wash, ice, soothe itch; Watch for spreading redness or fever (infection); Most do not need ER care. This species does bite or sting people. Fever, spreading redness, trouble breathing, or a child with many stings is professional care.

If you were bitten

  1. Wash, ice, soothe itch
  2. Watch for spreading redness or fever (infection)
  3. Most do not need ER care

Yellow sac spider vs Brown recluse

Pale, darker jaws, silken sac in a ceiling corner. No violin. Bites are usually immediate pain, not delayed recluse-type wounds. This is a leading “mystery night bite” spider in much of the country.

Range and season

Widespread in North American homes. Year-round indoors.

Homes across North America, walls and ceilings, year-round.

Widespread in North America in homes and gardens. Often blamed for mystery bites.

Year-round indoors; more wandering at night in warm months

Common questions

Did a yellow sac spider cause my mystery bite?

Possibly — they wander at night — but many “spider bites” are not spiders. Look for the spider if you can.

Is it as dangerous as a recluse?

No. Bites are painful and itchy, not typically necrotic like classic recluse wounds.

What does it look like?

A small pale spider with darker chelicerae, often in a silken tube in a corner.

Do yellow sac spiders bite people at night?

They wander at night. Painful welts noticed in the morning are often this spider, not a recluse.

Yellow sac spider vs brown recluse?

Sac: pale, no violin, eight eyes in two rows. Recluse: tan, violin, six eyes, south-central range.

Related identification pages