Family common name: xyelid sawflies
Genus: Megaxyela Ashmead, 1898
The Xyelidae hold status as the most primitive family, not only of the sawflies, but of all Hymenoptera. The xyelids are usually associated with a primitive plant group, coniferous trees (Ross 1932, Blank and Kramp 2017). The Macroxyelinae subfamily, however, is associated with angiosperms, and is likely the most primitive group of extant sawflies in the world (Smith and Schiff 1998).
Megaxyela adults are large, 8–15 mm in length, with distinctively long legs and orange/red coloration. Despite these easily noticeable characters, they are rarely observed (Smith and Schiff 1998, Blank et al. 2017)
Xyelidae can be distinguished from other families by the long ovipositor and the characteristic elongate third antennal segment wider than the remaining flagellum. Megaxyela can be distinguished from Xyela and Pleroneura by the large size and from Xyelecia by the location of the Sc2/R vein junction. It can be distinguished from Macroxyela by the shape of the clypeus and the carina around the eye (Goulet 1992, Blank et al. 2017).
Larvae are external leaf feeders recorded on species of Juglandaceae, including Carya illinoinensis (hardy pecan), other Carya sp. (hickory), Juglans cinerea (butternut), and other Juglans sp. (walnut) (Smith and Schiff 1998, Blank et al. 2017).
The female positions herself on the leaf with her abdomen at the apex, head towards the base. She deposits one egg on the upper surface of the apex of the leaf, then slowly folds the leaf upwards, longitudinally along the midrib, sealing it with an excreted glue-like substance (Smith and Schiff 1998). Larvae are large, 22–28 mm in length at maturity, cylindrical, with brown head capsule and spiracles, as well as long, 6-segmented antennae (Smith 1967b, BugGuide 2019). Typically, the larvae are situated wrapped around the base of a leaf. As the larvae mature, they feed on the young leaves of the tree. Around June, larvae will fall to the ground and build a cocoon to pupate (Smith 1967b, Smith and Schiff 1998).
North America: In North America, the range of Megaxyela is restricted to the eastern United States, from the Midwest east to the mid-Atlantic region, and Ontario, Canada (Blank et al. 2017).
Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Megaxyela
Details about data used for maps can be found here.