Xyelidae

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Taxonomy

Superfamily: Xyeloidea
Family: Xyelidae
Family common name: xyelid sawflies
Subfamilies: Archexyelinae, Macroxyelinae, Madygellinae, Xyelinae

Background

The family Xyelidae are recognized by most phylogenies as the most primitive sawfly family (Ross 1932). The two subfamilies have two distinct host preferences, one for coniferous and one for deciduous trees (Smith and Middlekauff 1987). The family can be easily recognized by the expanded first flagellomere (Goulet 1992).

Diversity

Xyelidae includes 52 genera and 158 species worldwide. About 5 genera and 38 species are Nearctic in distribution (Taeger et al. 2018).

North American genera

Macroxyela
Megaxyela
Pleroneura
Xyela
Xyelecia

Diagnostic characteristics

• pronotum evenly sloped; not extremely constricted medially (Goulet 1992)
• propleuron short ventrally (Goulet 1992)
• first tergite divided medially (Goulet 1992)
• hind tibia with 3–4 preapical spurs (Goulet 1992)
• fore tibia with 2 apical spurs (Goulet 1992)
• clypeus not as wide as distance between compound eyes (Goulet 1992)
• third antennal segment wider than fourth segment and about as long or longer than the remaining flagellum (Goulet 1992)

Host associations

In North America, Xyelidae feeds on coniferous trees in the family Pinaceae, and on angiosperm trees in the families Ulmaceae and Juglandaceae (Smith and Middlekauff 1987).

May be confused with

Xyelidae can be distinguished from other families by the wide and elongated third antennal segment (Goulet 1992).

Life history

Many species of Xyelidae are external leaf feeders. Some others bore into developing cones, buds, and shoots. One species, X. gallicaulis, is a gall-former. All known species are univoltine (Smith and Middlekauff 1987).

Distribution

World: This family’s range extends through North America, Europe, and Asia (Taeger et al. 2010).

North America: Xyelidae occurs throughout the United States and Canada, and south into Mexico (Smith and Middlekauff 1987).