In an earlier volume (I) the writer presented observations on the bionomics of the parasites and inquilines from the galls of Disholcaspis mamma (Walsh) on a bur oak (Quercus macrocarpa) near Urbana, Illinois. Not less than fifteen species of Hymenoptera were then associated with that gall. In the last two years this gall and its several inhabitants were rare or lacking there, but the leaf galls of Neuroterus verrucarum O.S. and N. niger Gillette were abundant on the same tree. The larvae of the latter cynipids are heavily parasitized by a chalcid, Tetrastichus verrucarii Balduf of the family Tetrastichidae. Observations on the habits and stages of the parasite and its hosts are given below. These records incidentally extend the known hymenopterous fauna of the above tree by four or more species.