Of the 37 species in this genus 19 are included here. All are wingless. Most have relatively wide distribution patterns (>100000 ha) but are found only within areas that have not been extensively modified. Yet 2 species (Megadromus antarcticus and Megadromus capito) have taken well to agricultural and urban habitats provided that the soils and surfaces are not disturbed regularly thus allowing larvae to develop within. The larvae and adults are active predators in the surface litter and loose soil. In late winter and spring, several species are known to nurse their eggs within cells under stones and logs and it is at this time the populations are most vulnerable. Rats, mice and probably stoats are predators on them.
Several species are yet to be formally described and one M. crassalis is relegated to a synonym of M. antarcticus, but its population in South Canterbury is considered endangered.