A small-scale experiment suggested that earthworms, snails, slugs, woodlice (Oniscus asellus, Trichoniscus pusillus provisorius) and centipedes (Lithobius crassipes L. variegatus)[long dash]but not enchytraeid worms or fly larvae (Sciara sp.)[long dash]living under loose bark of fallen beech branches in an English woods undertake mass movements into the surrounding leaf litter during severely cold weather, returning as soon as the weather improves. During very mild, moist weather in early spring, another experiment gave no evidence of similar movements between night and day.