An American cicada whose nymphs emerge in large numbers in a seventeen-year (or, in the south, a thirteen-year) cycle.
- ‘It is not known how periodical cicadas synchronize their life cycles over 13 or 17 years - or how they manage to count out the years.’
- ‘The bugs belong to the largest group, or brood, of periodical cicadas - insects that spend most of their lives as nymphs, burrowed underground and sucking sap from tree roots.’
- ‘But the lack of a viable predator control of the periodical cicadas doesn't mean the periodical cicadas have no predators, or no effect on their predators' lives.’
- ‘This year, thirteen-year cicadas will appear in Louisiana, Mississippi, Arkansas, Tennessee, Kentucky, Missouri, and Illinois, and seventeen-year cicadas will show up in Ohio, Pennsylvania, and West Virginia.’
- ‘The fact that periodical cicadas emerge after a prime number of years could be just a coincidence.’
We take a look at several popular, though confusing, punctuation marks.