The production of galls in species of Lactuca by the genus Aulacidea (Hymenoptera, Cynipidae) with special reference to the anatomy of the galls

Insect galls are plant malformations which owe their origin to stimuli originating with insects, and which serve to house these insects during part or all of their pre-adult life history. In this paper we deal with galls of the species of Aulacidea found infecting species of Lactuca in the eastern United States, together with a study of the insects and the phytophagous habits of the non-gall producing species.