Counts of spangle galls of 4 Neuroterus species in a plantation of young oak trees indicate that some leaves and trees are especially liable to bear galls of all species. Spangle galls of 2 species are most abundant on trees late in coming into leaf. The possibility of interspecific competition created by the tendency for all species to occur on the same leaves and trees is reduced by a special zonation of the spangle galls both on individual leaves and on trees. Galls of the alternate sexual generations of the 4 species also tend to occur together on the same trees and groups of leaves. They are less numerous than spangle galls and no zonation was observed. Two of the species in this generation, in contrast to their agamic generations, are most abundant on trees which come into leaf early, and the alternating generations tend to occur on different trees.