Armadillidium nasatum Budde-Lund, 1885


Armadillidium speyeri Jackson, 1923


GB IUCN status: Least Concern

ID Difficulty



Armadillidium species and Eluma caelata are readily recognised in the field by their truncated 'square' uropods that end flush with the body and their abilty to roll into a ball.

This pill-woodlouse (to 12mm) is reminiscent of A. vulgare.  However the narrow protruding scutellum (snout), reminiscent of the peak of a base-ball cap, is distinctive, as is the typically dark grey body marked with pale longitudinal stripes that give a semi-translucent appearance.  It forms an imperfect ball, with its antennae protruding, when disturbed.

J.P. Richards
J.P. Richards
Keith Lugg
Christian Owen

Distribution and Habitat

It occurs patchily across southern England and south Wales. It is characteristic of dry, sparsely vegetated habitats, both semi-natural and synanthropic, that are subject to high levels of insolation. This includes coastal grassland, limestone screes, disused limestone quarries, railway lines, industrial waste ground and garden centres (where it frequently occurs inside greenhouses).

It is typically found under rocks, stones, pieces of wood and other debris or amongst rubble, often with A. vulgare.

This summary is based on the detailed account in Gregory (2009).



Gregory, S. (2009) Woodlice and Waterlice (Isopoda: Oniscidea & Asellota) in Britain and Ireland.  Field Studies Council/Centre for Ecology & Hydrology.



BRC Code