IBALIID PARASITOIDS OF SIRICID WOODWASPS IN NORTH-AMERICA - 2 NEW IBALIA SPECIES AND A KEY TO SPECIES (HYMENOPTERA, CYNIPOIDEA)

Two new parasitic wasp species, Ibalia kirki and Ibalia arizonica (Ibaliidae), are described from the northern Arizona-New Mexico region. Both species were found among preserved specimens reared from woodwasp-infested coniferous trees in 1971-72 during a search for natural enemies of Siricidae for introduction to Australia. The two new species belong to a monophyletic group of four species within Ibalia (Ibalia). Three of these species are known only from southwestern North America, whereas the fourth, I. leucospoides (Hochenwarth), is widely distributed throughout the Holarctic region. The phylogeny and the historical biogeography of this group of species is discussed briefly. North American distribution records of all six I. (Ibalia) species known from the region are mapped. A key to the North American Ibalia species is presented, including a representative of the subgenus Tremibalia.