The cicadas of the family Cicadidae are a mostly tropical group of some 2,000 bug species. The burrowing nymphs feed on the juices of plant roots, and typically lead a subterranean existence for several years before surfacing and moulting, to emerge as winged adults. After mating, the female slits a tree twig with her ovipositor and lays several eggs in the resulting groove. The hatching nymphs drop to the ground and immediately burrow into the earth.