Greenhead flies are back and out for blood in Mass.

Move over, sharks. Greenhead flies are the real summer predator to fear.

The greenhead, a bloodsucking type of horsefly identifiable by their iridescent green eyeballs, have emerged from their eggs in salt marshes around the state.

Greenhead season coincides with beach season: the flies usually appear in June and stick around into August. This is a problem for beachgoers, as greenhead bites are painful. They are notorious for wreaking havoc on North Shore beaches along the Great Marsh, including Crane Beach in Ipswich, Plum Island Beach in Newburyport and Wingaersheek Beach in Gloucester.

Barry Noone is the director of the Northeast Massachusetts Mosquito Control and Wetlands Management District, a state agency tasked with controlling mosquitos and greenheads in Essex County. (While both bugs feast on blood, Noone said greenheads do not transmit illness like mosquitos.)

To tamp down on the greenhead population, Noone and his team set about 485 greenhead traps across Essex County each year. He estimates they capture about 5,000 to 8,000 flies yearly.

"Every year [traps are] full of thousands and thousands of flies," he said.

Noone said it would be "impossible" to capture all of the greenheads, which are a native species to the area. He said the goal of the traps is to "bring the population's level down just enough [so] hopefully there's comfort while people are at the beach."

While they're known as a North Shore pest, greenheads are prevalent in coastal marshes areas from Maine down to Florida. Noone said that pest managers on Cape Cod put out about 900 traps in the summer to snag the bloodsuckers.

Along with traps set by the pros, there are ways to protect yourself from becoming greenhead prey. Noone advises using a CDC recommended bug repellant that contains DEET, along with wearing long sleeves and pants. These flies prefer darker colors, so Noone suggests wearing light colored clothing.

If you're headed to the beach, Noone recommends drying off right when you get out of the water, because the bugs are attracted to salty scents and sweat. Greenheads also prefer still weather, so windier days are a safer bet.