GEOGRAPHIC AFFINITIES OF THE NORTH AMERICAN MECOPTERA

Mecoptera of the Nearctic Region are, in general, more like those of the eastern Palaearctic than of any other faunal region. But the fossil record shows that our major extant genera have been in the northern continents since Early Cenozoic. Panorpidae and Panorpodidae probably entered North America by way of Beringia in the Eocene or Oligocene. Nearctic Bittacidae probably came from the Neotropical Region, but a few exhibit peculiar affinities with some eastern Asiatic species, suggesting migration out of the Nearctic into the Palaearctic. Boreidae appear to have been of North American origin but are now Holarctic; they are unknown as fossils. The Meropeidae were probably widespread in mid–Mesozoic but now are found only in eastern North America and western Australia.