A small family of about 100 species worldwide, with five species in Europe, two of which have ben recorded in the British Isles.
Pine Processionary a possible rare migrant recorded in Kent in 1874 and Berkshire in 1966.
Oak Processionary an immigrant. In 1992, two were reported at Dungeness and one at nearby Greatstone on 9 and 10 August. In 1995, 12 were recorded between 3 and 13 August, in Kent, Essex, Cambridgeshire, Suffolk, Norfolk and Northamptonshire. The last was recorded in the Isle of Wight in 1998.
(Taken from Waring and Townsend’s Field Guide to the Moths of Great Britain and Ireland)