What is "periodical cicada"

n. Certain species of cicadas, especially in genus ''Magicicada'', which are known for their 17- and 13-year life-cycles, during most of which they develop underground, emerging in large numbers for a short time as large and audible adults, all those emerging in a year constituting a brood.

n. North American cicada; appears in great numbers at infrequent intervals because the nymphs take 13 to 17 years to mature [syn: seventeen-year locust, Magicicada septendecim]