Male and female cicadas mate in the summer immediately after becoming adults. After they mate, the female places the eggs in small slits she makes in tree twigs and branches. About one month later, eggs will hatch and tiny nymphs will fall to ground and burrow below. They will stay underground for the next 17 years until they are ready to molt into adults, as their parents did.
Nymphs feed on tree and grass roots. They develop strong front legs as they burrow through the soil underground. When they mature, the cicadas burrow out of the ground, creating little mud chimneys which are visible in yards. This occurs in late April or early May. It will leave the burrow when it is ready to molt to an adult. Some experts believe this happens when the temperature is about 64 degrees Fahrenheit.
When the cicada leaves the burrow to become an adult, it climbs into a nearby tree or bush to shed its skin. It molts into an adult cicada. When this happens, a number of cicada skins can be seen on the ground. The adult cicadas live for about two to six weeks, long enough to mate and produce new nymphs.
Cicadas can be noisy. After they shed their skin and become adults, male cicadas begin to sing. Each species has a song that is unique to it. The Magicicada septendecim sings in the morning and sounds like "pharoah." M. cassini sings in mid-to late afternoon and sounds as if someone's starting a lawn mower. M. septendecula sings around midday with a sound like a lawn mower that's "chugging along." A pair of vibrating structures located behind the wings produce the sounds.