Body length of adult females 4.8 - 7.3mm, of adult males 4.4 - 6.0mm.(1)
Range
Imported (from Europe) and has been officially collected in these localities so far, according to published literature:
      Canada: British Columbia(2), Newfoundland(1)(2), Nova Scotia(1)(2), New Brunswick(1)(2), Quebec(1)(2), Ontario(1)(2)
      USA: Maine(1), New Hampshire(1), Washington (first record for the state from Orcas Island in 2002, see here)
Habitat
Usually found on man-made structures, like barns and garages.
Remarks
Evidence indicates that S. bipunctata, which closely resembles the native S. borealis in size, colour, microhabitat, diet activity, prey selection and utilization, life history, and sexual behaviour, can displace S. borealis.(3)
~ www.conservation.unibas.ch - (PDF) Evidence for displacement of a North American spider, Steatoda borealis (Hentz), by the European species S. bipunctata.