Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

"Symphyta" - Sawflies, Horntails, and Wood Wasps

Another Illinois sawfly - Dolerus Trichiosoma - Trichiosoma triangulum Mystery fly - Tethida barda - female Allantus viennensis? - Allantus viennensis Macrophya flavicoxae Common sawfly - Dolerus Sawfly - Tenthredo ID this colorado bug - Cephus cinctus
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
Synonyms and other taxonomic changes
A paraphyletic grouping of more basal hymenopteran lineages, previously known as Symphyta; phylogenetic relationships summarized in(1). The families are arranged into 7 superfamilies: Tenthredinoidea, with 6 families (Argidae, Blasticotomidae, Cimbicidae, Diprionidae, Pergidae, Tenthredinidae) is by far the largest; Siricoidea with two families (Anaxyelidae, Siricidae); Pamphilioidea with two families (Megalodontesidae [=Megalodontidae, not in our area], Pamphiliidae); while the remaining four superfamilies—Cephoidea, Xiphidrioidea, Xyeloidea, and Orussoidea—each consist of a single family.(2)
Explanation of Names
"Sawfly" refers to the sawlike ovipositor cutting into plant tissues to deposit eggs(3)
About 8000 spp. in ca. 800 genera of 14 families worldwide; 1245 spp. in ca. 140 genera of 13 families in the Nearctic Region(4)(5) and 1100 spp. in our area (Dave Smith's estimate, pers. comm. to =v= 5/2/10); >700 spp. in Canada(6), ~350 in VA(7)
(the only family still missing in the guide is monotypic Anaxyelidae from the Pacific Coast; the only family not represented in our area is Megalodontesidae, restricted to temperate Eurasia)
The adults may resemble other hymenopterans, but lack the characteristic "wasp waist". Females may have conspicuous, impressive ovipositors but are unable to sting.
Many sawfly larvae resemble lepidopteran caterpillars (how to distinguish), but have at least six pairs of prolegs (no more than five pairs in caterpillars, with the exception of the Megalopygidae, which has 7); others are legless and may be slimy (often called 'slugworms' or just 'slugs').
Keys to genera of Canada & n. US in(6)


Worldwide and throughout NA
Most sawfly larvae feed externally on tree/shrub foliage; some mine leaves, a few form galls. Some bore in stems (Cephidae), fruits, or wood (horntail and woodwasp larvae), and in those legs are reduced or absent. The parasitic family Orussidae is the only exception. Some adult sawflies feed on nectar or pollen.(3)
Life Cycle
Usually have one generation a year and overwinter as mature larva or pupa in a cell/cocoon in the ground or in otherwise protected place; in larger spp. the cycle may take more than one year(3)
Works Cited
1.Evolution of the Insects
David Grimaldi and Michael S. Engel. 2005.
2.Phylogeny and classification of Hymenoptera
Sharkey M.J. 2007. Zootaxa 1668: 521–548.
3.Borror and DeLong's Introduction to the Study of Insects
Norman F. Johnson, Charles A. Triplehorn. 2004. Brooks Cole.
4.Blank et al. (2012) ECatSym: Electronic World Catalog of Symphyta (Insecta, Hymenoptera). Program version 4.0 beta
5.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
6.The genera and subgenera of the sawflies of Canada and Alaska (Hymenoptera: Symphyta)
Goulet H. 1992. The insects and arachnids of Canada, Pt. 20. Ottawa: Agriculture Canada. 235 pp.
7.List of the Sawflies (Hymenoptera: Symphyta) of Virginia
Smith D.R. 2006. Banisteria 28: 3-23.