A very large and robust millipede (to 48mm in length by 4mm in diameter), typically very dark, almost black, in colour and with a projecting club shaped telson (tail) otherwise only seen in Cylindroiulus punctatus (a much smaller pinkish-brown species). It is most likely to be confused with Cylindroiulus caeruleocinctus, but this species is smaller and lacks the projecting telson.
Distribution and Habitat
This species is widespread but uncommon in Britain and Ireland. It has been recorded most frequently from south east England with few records from Scotland, Wales or Ireland. In Britain and Ireland, it has been recorded most frequently from woodland (48% of records) but the analysis does not suggest an association with this habitat. It has been recorded in a range of different habitats but not so far in heathland, moorland or wetland and not in strongly synanthropic sites. In Europe, Kime (1990a) considered C. londinensis to be a woodland animal whilst Demange (1981) gave it as frequent in woodland and open land up to 2000 m. Kime (1999) considered the species to be most frequent on calcareous soils but noted it also occurred on free draining acidic soils. Analysis of the recording scheme habitat data does not support an association with calcareous soils although there is some evidence for an association with free draining sandy soils. Cylindroiulus londinensis has a strict Atlantic distribution. In addition to Britain and Ireland, it is only known from the western half of France and from northern Spain (Kime, 1999). Adults have been found in each month from April to August and in November and December.