The gall fly is a wasplike insect belonging to the family
Cynipidae of the order Hymenoptera. The members of this large family are small in size, measuring less than a quarter of an inch, and are generally black, brown, or lighter in color. The smooth shiny body may or may not have wings, depending upon the species. The antennae are slender and tapering. Gall flies deposit their eggs within the tissues of plant hosts, individual species causing the formation of characteristic galls. The most important hosts of gall flies are oaks. Among the well known genera are
Andricus,
Amphibolips,
Diplolepis Disholcaspis, and
Rhodites.