To some, they’re wondrous. To others, they’re just annoying.

They are the 17-year cicadas — billions of insects, now underground and due to emerge en masse most likely starting next month.

The nymphs are expected mostly in limited areas of Ohio and West Virginia. But, experts say, there is also the potential in June for their arrival in a snippet of Suffolk County.

After all those years in the making and prompted by warming soil, the insects crawl up through tunnels to the ground-surface, make a distinctive racket, breed and die — all in just about four weeks’ time, assuming they’re not eaten. They do make a mark, though, as they leave behind offspring, programmed to poke their heads above ground in 2033.

Nonbiting and nonstinging, cicadas probably won’t hurt plants, though a large grouping could damage shrubs and small trees, as females “do pierce/cut small branches on woody plants to insert their eggs,” according to Magicicada.org, a site devoted to the Magicicada species.

Their real hallmark though is the males’ collective mating call, also called a chorus. The din of those that emerge on Long Island — the Magicicada septendecim — is akin to the whirring of machinery, an eerie sound, reminiscent of flying saucer landings in 1950s science-fiction movies, said Chris Simon, a professor in the department of ecology and evolutionary biology at the University of Connecticut.

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She’s also co-author of a 1982 article on Long Island’s periodical cicadas in the Journal of the New York Entomological Society.

The batch that emerges this year, known as Brood V, could well make an appearance in the Wildwood State Park area in Wading River, according to another site, cicadamania.com.

Their short-lived excursion into sunlight gets launched when soil 7 or 8 inches underground reaches a stable 65 degrees, she said.

For the most part, that usually happens in late May to early June on Long Island and should not be confused with the arrival in mid- to late summer of the annual cicadas, says Dan Gilrein, entomologist with Cornell Cooperative Extension of Suffolk County.

Nicknamed by some as the “Rip Van Winkle of the insect world,” the periodical cicada adults can be recognized by their black bodies, red eyes and orange wing veins. That label is off-base, Simon says, as the insects are not sleeping, “but rather growing up.”

Gilrein said he would also like to correct a misperception. “Readers,” he said in an email, “should also know that cicadas are NOT the locusts of biblical and other plagues, a point of common confusion.”

Back in 1999, the early June Brood V emergence in the Wildwood State Park area and just northeast of what’s now Calverton Executive Airpark, was considered moderate, with a chorus of mating calls that gradually got louder over two weeks, Simon said.

She and her colleagues are “really anxious to see what happens” this year, with the chance, too, for small pockets to emerge in or around Calverton and Wading River. Any sightings can be reported on Magicicada.org.

In some cases, cicada populations have been known to increase, while others disappear altogether — which was the case, she said, with 2004’s Brood X, when expected sites in Bohemia, Shirley and Connetquot River State Park Preserve saw no cicadas at all or the few that did emerge promptly eaten by birds.

Though experts say there’s no clear reason for diminishing numbers, some point to land development, introduced pest birds or pesticide use as possible contributing factors.

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The varying broods are at different stages of their cycles, with the Island’s most abundant group, Brood XIV, still percolating underground and scheduled to emerge in 2025.