This species is similar in appearance to the common Proteroiulus fuscus, but differs in subtle morphological characters. Identification should be undertaken by examination of male gonopods where possible.
Distribution and Habitat
This is a widespread but uncommon species in Britain and Ireland. In Scotland it has not been recorded from north of Montrose. Analysis of the habitat data suggests a very strong association with buildings and with urban sites. This synanthropic tendency is strongest in the north of England and in Scotland where the species is usually recorded from gardens and glasshouses. Further south it can be found in the same habitats but has also been collected from leaf litter or under bark in deciduous woodland. Kime (1999) suggested this might be its natural habitat. Pedroli-Christen (1993) also reported the species from calcareous grassland in Switzerland. Kime (2004) noted that many of the semi-natural sites where this species occurs are on calcareous soils. There is insufficient data available from Britain and Ireland to check the validity of this statement. The species appears to be native to the Atlantic zone of north west Europe but occurs as a synanthrope further north and east and has been introduced to Madeira, the Azores and North America (Kime, 1999). Adults have been found from February to June and from September to November. They probably occur throughout the year. The life history of this species has not been studied in detail but it is likely to be similar to that of Proteroiulus fuscus.