Bug FAQBull-headed sac spider
Trachelas pacificus · Order: Araneae · Family: Trachelidae
The bull-headed sac spider is a true spider in the family Trachelidae. It lives in the United States and Mexico, especially Arizona, California, Nevada and Baja California. Adults are found inside houses throughout the year.
Source: Wikipedia
How to recognize it
Trachelas pacificus belongs to the spider family Trachelidae.
Source: Wikipedia
Is it a pest in the house?
They are often encountered inside houses.
Source: Wikipedia
Where it lives
These spiders are commonly found inside homes.
Source: Wikipedia
When you see it
Adults can be seen year-round.
Source: Wikipedia
Where it comes from
They occur in the United States and Mexico, notably in Arizona, California, Nevada and Baja California.
Source: Wikipedia
Where it is found in the US
Recorded in 7 of 51 states and DC. Most records: California, Texas, Arizona, Oklahoma, Colorado, Florida, Massachusetts.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Where might I find a bull-headed sac spider in my home?
They are commonly found inside houses throughout the year.
Source: Wikipedia
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Trachelas_pacificus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.