During the past summer I noticed that the wasp, Ancistrocerus capra (De Sauss) was frequently to be taken on the Locust Tree (Robinia pseudacacia), so one afternoon about the middle of August I thought I would try to discover what was the attraction. I did not have to wait long for a wasp and soon found one which appeared busy hunting. Many of the leaves on this particular tree had the edges folded over and swollen, the work of some gall maker; she examined these leaves very closely, but I hardly thought that what was in them would be of any use to a wasp the size of capra.