About Polystepha pilulae (Beutenmüller, 1892)
Polystepha pilulae is a species of midge. The larvae of this midge induce circular galls that develop between veins on the upper surface of oak leaves belonging to the red oak group (Quercus sect. Lobatae). These galls can be either flat or convex in shape, have thick walls, and are reddish-brown in color. They measure 3 to 4 millimeters in diameter.