University of California Publications in Entomology
THE GENUS Xyela is widely distributed in the Holarctic region, and may extend across the equator into Sumatra, together with its host, the genus Pinus. The genus belongs to the small and ancient family Xyelidae, which is known from a lower Jurassic fossil, Liadoxyelct praecox Martynov (Marty nov, 1937). This is the oldest hymenopteran fossil that can be placed in a modern family. With our present inadequate knowledge, neither the time nor the place of origin of Xyela can be hypothesized.
Burdick, Donald J., "A Taxonomic and Biological Study of the Genus Xyela Dalman in North America" (1961). Bu. Paper 10.
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