Synonyms and other taxonomic changes
Cimbex americanus Leach
= Cimbex americana
[!] - Cimbex
is masculine so a female epithet is in error (see iNaturalist
Explanation of Names
Cimbex americanus Leach, 1817
from the New Latin americānus ('American, of or related to the Americas')
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
Larva Pupa Adult male Adult female Mating pair
not considered a forestry problem, but can defoliate shade/ornamental elms and willows (Forestry images