adult 18-20 mm, larva up to 50 mm
The largest North American sawfly. Larvae yellowish-white with black dorsal stripe. While feeding, the larvae usually coil their posterior around a leaf or twig. At rest the larvae roll into a characteristic tight coil. The larvae spin tough, papery cocoons in the litter or just below the surface of the soil. Pink coloration is not common, most larvae are green to yellow in color.
Adult has glabrous thorax with white/yellow spot above, orange antennae. Females commonly have a yellow banded abdomen.
hosts include elm (Ulmus), maple (Acer), birch (Betula), willow (Salix), and basswood (Tilia); adults girdle bark on twigs
Larvae have chemical defenses, ejecting fluids from glands near spiracles; often coil hind end around twigs; overwinter in cocoons, and pupate in spring
not considered a forestry problem, but can defoliate shade/ornamental elms and willows (Forestry images