Abstract Biological control efforts in California directed against the linden aphid (Eucallipterus tiliae) have been predicated on the basis that the aphid is native to Europe. Although several European parasitoids have become established and attackE. tiliaein California, complete control has not been achieved; the aphid is a problem in Europe as well. New records ofE. tiliaefrom eastern Asia suggest that the aphid may be native there. This area has the greatest species diversity of both the host genus (Tilia) and the other linden-feeding drepanosiphid aphids. It is recommended that any further efforts for locating importable natural enemies be focused in this region.