Gall maker: Cecidomyia pellex, a species of midge (Order Diptera, Family Cecidomyiidae)

Shape and Size: Referred to as the "ash bullet gall" because of its round, bullet-like appearance; the gall in the illustration is decaying, giving it a brown, wrinkled appearance. Gall size apparently variable; example is roughly 1 cm in diameter

Location: Occur on top of Fraxinus (ash) leaves, summer.

Color: Possibly variable.