Trillions of cicadas are set to return to the United States after last appearing back in 2004 in large numbers, Newsweek reported.The cicadas are set to hit the following 15 states: Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia, as well as Washington, DC.The swarms of these insects can be quite dense, reaching up to 1.5 million per acre. In addition, they are infamous for their loud mating calls, which, according to National Geographic, can be as loud or even louder than 100 decibels – louder than the sound of an approaching subway train.The cicadas will not cause any long-term damage to trees, nor will they enter homes, explained Michael J. Raupp, emeritus professor of entomology at the University of Maryland, in an interview with Newsweek. He also reassured that the bugs cannot attack pets or small children.Raupp said that while the idea of so many insects may sound terrifying, he hopes that people will use the opportunity to see a biological phenomenon taking place near them. These cicadas largely belong to the Magicicada septendecim species, characterized by its broad orange stripes and patch of orange between their eyes. Magicicada cassini and Magicicada septendecula are included among them, and are distinguished by their black abdomens.In 2020, scientists were concerned about Asian Giant Hornets, dubbed "murder hornets" by some researchers after they appeared in North America and were a risk to local bee populations. These hornets killed up to 50 people a year in Japan. They are the world's largest hornets, being an average of nearly two inches long, with a stinger a quarter of an inch long packed with a potent venom.