Most phylogenies position Xyelidae as the most primitive family of all Hymenoptera. The xyelids are usually associated with a primitive plant group, coniferous trees (Ross 1932, Blank and Kramp 2017). The subfamily Macroxyelinae, however, is associated with angiosperms, and is likely the most primitive group of extant sawflies in the world (Smith and Schiff 1998).
Macroxyela 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).
Xyelidae can be distinguished from other families by the long ovipositor and the characteristic elongate third antennal segment which is wider than the remaining flagellum. Macroxyela can be distinguished from Xyela and Pleroneura by their large size and from Xyelecia by the location of the Sc2/R vein junction. It can be distinguished from Megaxyela by the shape of the clypeus (Goulet 1992).
Life history information is only known for M. ferruginea. Larvae are large, 14–18 mm in length at maturity, cylindrical, and green with brown head capsule and spiracles, as well as long, 6-segmented antennae. 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 loosely-compacted cocoon of sand and silk to pupate (Smith 1967b).
Adults fly during late March to early April only on warm, sunny days. Males emerge during the first few weeks and females during the last few weeks of the flight period. Macroxyela are univoltine (Smith and Schiff 1998).
World: Macroxyela is a North American genus (Taeger et al. 2010).
North America: The two species of Macroxyela have overlapping ranges in the Midwest and eastern regions of the United States and southern Canada, from as far south as Louisiana, as far north as Quebec, from around the Mississippi River east to the Atlantic coast. There are a few aberrant collections farther west, in Idaho and Arizona (Smith and Schiff 1998).
Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Macroxyela
Details about data used for maps can be found here.