scary caterpillar, birch sawfly larva, cimbex femoratus of yellow color with black dots on sides and line on back

animal back big biology birch black caterpillar cimbex cimbicidae closeup crawl creepy details eating entomology face femoratus forest glide green hymenoptera insect invertebrate jaws large larva larvae larval leaf line maggot nature pest pests sawfly scary skin spotted stage strange striped symphyta wasp weird white wildlife worm yellow