The hackberry nipple gall is about 1/8 inch in diameter and is nearly 1/4 inch tall. The adult psyllid looks like a miniature cicada. They are usually 1/8 inch in length and have hind legs adapted for jumping or springing from a resting position into flight. Thus, their nickname "jumping plant lice." The eggs are usually yellow to white while the nymphs are a golden yellow. The hackberry blister gall measures 1/8 inch in diameter.