Context

 In a rare double-emergence of cicada broods, Brood 13, which emerges every 17 years, and Brood 19, which emerges every 13, are going to join together for the first time since 1803, in eastern United States.

What is a cicada?

• Cicadas are large, robust insects, with transparent wings and large compound eyes.
• They are known for their loud chirping and tendency to leave behind mounds of exoskeleton
• They have a distinctive corrugated exoskeletal structure on the sides of their abdomen called a ‘tymbal’, and it’s this organ that produces the loud buzzing sound.
• There are more than 3,000 species of cicada worldwide, which fall into roughly two categories:
  • Annual cicadas, which are spotted every year
  • Periodical cicadas, which spend most of their lives underground and only emerge once every decade or two.