There are four well-known, introduced species of Julidae in New Zealand: Cylindroiulus britannicus, Ophyiulus pilosus, Ophyiulus verruculiger and Brachyiulus pusillus. A fifth species needs confirmation. The first two are very common and the last two moderately so. They are abundant in wet urban garden and agricultural/horticultural environments with the first species also present in some native environments that have been disturbed by human activities such as picnic areas in native forest, even trampers' huts on the Heaphy and other tracks. Although present in those and similar sites the species have not entered deep into the forest. There is some factor/s limiting their further occupation of the native environment. Ophyiulus pilosus has sometimes caused great concern to people moving into their new home. During the building of the house much vegetation is destroyed and if the house is laid on a concrete slab calcium salts leach into the surrounding soil. The rotting grass etc and the calcium salts provide a great source for the fungal food of the millipede which in Spring can reach large populations. The males will wander around on warm humid nights and there are instances of hundreds of millipedes entering houses and dying along the edges of newly laid carpets. In the 1960's and later carpets were treated with insecticides before laying. The dead bodies were of great concern to the new home owners! Cylindroiulus britannicus and the blaniulids are known to attack tubers in damp soil.