Diprion pini

The common pine sawfly, Diprion pini, is a sawfly species in the family Diprionidae. The adult male is dark brown or black with comb-like antennae; the female is striped black and yellow. The female lays some 100 C150 eggs on pine needles. The caterpillars are yellow-green, gregarious, and feed on pine needles. The next generation of adults can emerge from pupae the same year, or the pupae can go into diapause for a year or more. The species is widespread throughout Europe and Russia. The insect is a serious pest of economic forestry, capable of defoliating large areas of pine forest. The Scots pine, Pinus sylvestris, is the main host but other pine species are also attacked. Since the species grazes until late autumn, weakened trees often die in winter. Control involves aerial spraying of insecticides, or biological control with parasitoid wasps. The species was first described by Carl Linnaeus.

from Wikipedia