The oak eggar (Lasiocampa quercus) is a common moth in the family Lasiocampidae found in Europe and northern and western parts of Asia. The larvae feed on a wide variety of plant species, low down, including blackthorn, hawthorn, viburnum, dogwood, ivy and ling, but are not known to feed on oak. They can be infected by baculoviruses, which change their behaviour and cause them to climb out of the protection of low scrub and leave them open to predation, facilitating the spread of infection. Oak eggar larvae eventually pupate on the ground inside a silken cocoon, the exterior of which is hard and yellowish, and resembles an acorn, from which the common name "oak eggar" is derived. This oak eggar larva in the form of a fourth-instar caterpillar, with a body length of 53 millimetres (2.1 inches), was photographed on a branch in Keila, Estonia. The photograph was focus-stacked from 59 separate images.