Adult psyllids each have two pairs of membranous wings (of unequal lengths) always present, with characteristic venation and hairs along the veins. Hind legs are saltatorial, with large, fixed coxae; tarsi are each two-segmented, with a double terminal claw. Reproduction is sexual; pedunculate eggs are laid at least partly embedded in plant tissue; and there are five immature stages, all mobile but sometimes developing within leaf galls or, occasionally, under non-living covers (lerps).