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For Insects, Spiders & Their Kin
For the United States & Canada
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Species Cimbex americana - Elm Sawfly

horse fly/yellow jacket cross? - Cimbex americana Large white caterpillar - Cimbex americana Hymenoptera or mimic?  Ontario Canada - Cimbex americana fly - Cimbex americana Wasp? - Cimbex americana Elm Sawfly larvae - Cimbex americana Cimbex americana - Elm Sawfly - Cimbex americana aproximatly 1 to 11/4 inch long very aggresive - Cimbex americana
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon ("Symphyta" - Sawflies, Horntails, and Wood Wasps)
Family Cimbicidae (Cimbicid Sawflies)
Genus Cimbex
Species americana (Elm Sawfly)
Explanation of Names
Cimbex americana Leach 1817
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.
most of NA (map)
adults May-Jun(1)
hosts include elm (Ulmus), maple (Acer), birch (Betula), willow (Salix), and basswood (Tilia); adults girdle bark on twigs
Life Cycle
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)
Works Cited
1.National Audubon Society Field Guide to Insects and Spiders
Lorus and Margery Milne. 1980. Knopf.