This process is called sublimation. The opposite (deposition) is where a gas turns directly into a solid. Sublimation occurs if the pressure and temperature are right for the specific substance, so that the solid phase in a phase diagram borders the gas phase.
Most cicadas go through a life cycle that lasts from two to five years. Some species have much longer life cycles, such as the North American genus, Magicicada, which has a number of distinct broods that go through either a 17-year or, in some parts of the world, a 13-year life cycle.
The growing cicada then spends the next 13 to 17 years underground as a nymph. Juvenile cicadas live at depths of 30 centimetres or more and subsist on the juices of plant roots until the final year. When the soil temperature reaches about 18 degrees Celsius, they burrow their way to the surface.