This map has been generated by Mapmate 30/12/2011

Rare at the time of the 1991-1992 survey with records from: a railway bridge at Cadishead (SJ704926); Salford viaducts (SJ8298 and at sites lost to development that included an abandoned pit building at Sod Hall (SD7204) and an old wall above the canal dock, Boothstown (SD726004) now a residential area known as the Moorings. The numerous additional dots on the distribution map indicate that this species has clearly increased in frequency since the time of the 1991-1992 survey.