Sawflies are wasp-like insects that are in the suborder Symphyta within the order Hymenoptera, alongside ants, bees, and wasps. The common name comes from the saw-like appearance of the ovipositor, which the females use to cut into the plants where they lay their eggs. The name is associated especially with the Tenthredinoidea, by far the largest superfamily in the suborder, with about 7,000 known species; in the entire suborder, there are 8,000 described species in more than 800 genera. Symphyta is paraphyletic, consisting of several basal groups within the order Hymenoptera, each one rooted inside the previous group, ending with the Apocrita which are not sawflies.
Horntail or wood wasp are any of the 150 non-social species of the hymenopteran family Siricidae, a type of wood-eating sawfly. The common name "horntail" derives from the stout, spine-like structure at the end of the adult's abdomen, which is used to pierce the host's bark to allow the eggs to be inserted into the wood. A typical adult horntail is brown, blue, or black with yellow or red parts, and may often reach up to 4 cm (1.6 in) long. The pigeon horntail can grow up to 5 cm (2.0 in) long, among the longest of all Hymenoptera.
The Orussidae or the parasitic wood wasps represent a small family of sawflies ("Symphyta"). Currently, about 93 extant and four fossil species are known. They take a key position in phylogenetic analyses of Hymenoptera, because they form the sister taxon of the megadiverse apocritan wasps, and the common ancestor of Orussidae + Apocrita evolved parasitism for the first time in course of the evolution of the Hymenoptera. They are also the only sawflies with carnivorous larvae.
The Xyelidae are a comparatively species-poor family of sawflies, comprising about 80 extant species in five genera worldwide, and is the only family in the superfamily Xyeloidea. The fossil record of the family is extensive, comprising more than 120 species and including the oldest fossil Hymenoptera species dating back to the Triassic, between 245 and 208 million years ago. Xyelidae are to be regarded as living fossils since they represent one of the oldest lineages of insects and include still extant forms.
The Pamphilioidea are a small superfamily within the Symphyta, containing some 250 living species restricted to the temperate regions of Eurasia and North America. These hymenopterans share the distinctive feature of a very large, almost prognathous head, which is widest ventrally.
The Megalodontesidae are a small family of sawflies, containing a single living genus, Megalodontes, with some 40 species restricted to the temperate regions of Eurasia. Larvae of Megalodontesidae feed on herbaceous plants. They are distinguished from the closely related Pamphiliidae by their serrate or pectinate antennae.
Pamphiliidae is a small family within Symphyta, containing some 200 species from the temperate regions of North America and Eurasia. The larvae feed on plants, using silk to build webs or tents, or to roll leaves into tubes in which they feed, thus earning them the common names leaf-rolling sawflies or web-spinning sawflies. Some species are gregarious and the larvae live in large groups. Fossils of Pamphiliidae have been dated to the Jurassic period.
The Tenthredinoidea are the dominant superfamily of sawflies within the Symphyta, containing some 8,400 species worldwide, primarily in the family Tenthredinidae. All known larvae are phytophagous, and a number are considered pests.
Trigonalidae is a family of parasitic wasps in the suborder Apocrita. They are the only living members of the superfamily Trigonaloidea. Trigonalidae are divided into 2 subfamilies; Orthogonalinae and Trigonalinae. These wasps are extremely rare, but surprisingly diverse, with over 90 species in 16 genera, and are known from all parts of the world. It is possibly the sister group to all Aculeata.
Ulteramus is an extinct genus of parasitic wasp in the sawfly family Pamphiliidae. The genus is solely known from an Eocene fossil found in North America. At the time of its description the new genus was composed of a single species, Ulteramus republicensis.
Abia is a genus of sawflies belonging to the family Cimbicidae. This genus includes several stout sawflies commonly encountered in Europe. Several species in the genus were formerly classified under the genus Zaraea, but this name is now treated as a synonym, as it is not monophyletic.
Acantholyda is a genus of sawflies.
Pseudopachystylum is a genus of flies in the family Tachinidae. It is a parasitoid of sawflies from the family Pamphiliidae.
Nematinae is a subfamily of sawflies belonging to the family Tenthredinidae. It contains over 1250 described species in ~40 genera. Members of this subfamily feed on a wide range of plants and employ a wide range of feeding habits, both internally and externally, on their host plants.
Pamphilius is a genus of leaf-rolling sawflies within the Symphyta belonging to the family Pamphiliidae.
Cephidae is a family of stem sawflies in the order Hymenoptera. There are about 27 genera and more than 160 described species in Cephidae.
Xyela is a genus of sawflies, belonging to the family Xyelidae.
Aprosthema is a genus of insects belonging to the family Argidae.
Cephalcia is a genus of insects belonging to the family Pamphiliidae.
Megaxyela is a genus of sawflies in the family Xyelidae. There are about 13 described species in Megaxyela, found in the eastern Nearctic and in the southeastern part of East Asia. Two fossil species have been discovered, in Colorado and Shandong, China.
