Introduced to California from Europe, possibly via the naval base at Port Hueneme, CA.(2)
It is native to Madeira and the Canary Islands, but spread to Great Britain, Portugal to Italy, and Algeria so far. At the time of publication of Vetter & Rust's 2012 paper, it had only been officially collected from Ventura County, California. However, since then, BugGuide records indicate that it is also living in at least Orange, Alameda, Monterey, and Santa Clara counties.