Pill bug

Description. Armadillidium vulgare may reach a length of 18 millimetres (0.71 in), and is capable of rolling into a ball when disturbed; this ability, along with its general appearance, gives it the name pill-bug and also creates the potential for confusion with pill milipedes such as Glomeris marginata.
Distribution. It is able to regulate its temperature through its behaviour, preferring bright sunshine when temperatures are low, but remaining in shadow when temperatures are high; temperatures below −2 C (28 F) or above 36 C (97 F) are lethal to it.