A new, larger type of cicada is emerging — and they have big black eyes and "like to scream"

Billions of Brood X cicadas temporarily emerged this summer after being underground for 17 years. They were only around for a few weeks — but now, a new and larger type of cicada has arrived to take their place. 

Officials at Maryland's Catoctin Mountain Park, a unit of the National Park Service, said the insects are called dog-day cicadas since they come out "during those hot dog days of summer." The insect has bright green, see-through wings and large eyes, and it takes two to three years for this particular type of cicada to develop and emerge from underground. But unlike Brood X, the population makes an appearance every year.  "They are much larger and have black eyes," Catoctin Mountain Park wrote in Facebook post. "Like all cicadas, they are harmless and like to scream."