Synonyms and other taxonomic changes
Cimbex americanus Leach, 1817
=
Cimbex americana [!] -
Cimbex is masculine so a female epithet is in error (see
iNaturalist and
BugGuide discussions)
Explanation of Names
Cimbex americanus Leach, 1817
from the New Latin americānus ('American, of or related to the Americas')
Size
adult 18-20 mm, larva up to 50 mm
Identification
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.
Food
hosts include elm (Ulmus), maple (Acer), birch (Betula), willow (Salix), and basswood (Tilia); adults girdle bark on twigs
Life Cycle
Eggs are deposited in pockets cut into leaf tissues.
(2)
When larvae become full grown, they crawl to the ground and spin tough, papery cocoons in the litter of just below the soil surface.
(2)
One generation per year
(2)
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
Remarks
not considered a forestry problem, but can defoliate shade/ornamental elms and willows (
Forestry images)