Photo at Jinju, South Korea Porcellio scaber This animal is common and widely distributed and it might in fact be the most common in the garden due to the fact that it can survive dry places. Unlike other common species, this animal possesses pseudotracheae, just like the pill-bug, thus allowing it to breathe in a drier climate. This species is about 16 mm long and 6-7 mm wide. The dorsal surface is covered with prominent tubercles and is rarely very shiny. It is usually a rather dark steely grey colour, but lighter mottled varieties do occur, and young specimens are very often mottled with yellow and brown. Porcellio scaber can be found under stones and logs and it is the commonest species in greenhouses, but it is even more common in bark crevices and on old walls. If you take a torch to a tree trunk or a wall on a humid night, you will probably be very surprised at the numbers of woodlice that you will find, and most of them will be Porcellio scaber From: http://www.the-piedpiper.co.uk/