LEMONT, Ill. – Dan Soluk is walking the floor of the Des Plaines River valley near Lemont when one appears.

Among the swarms of other insects, the distinctive helicopter profile of the Hine’s emerald dragonfly emerges. The young male is one of just a few hundred of these insects still alive in Illinois.

All of them live in the far southwestern Chicago suburbs.

“I can’t believe he is showing off like that,” Soluk said as the dragonfly bobs and weaves, searching for smaller insects to devour.

This adoring audience gets to witness the spectacle because of Interstate 355’s south extension, a project that could have meant the dragonfly’s demise.

The construction of I-355 this summer afforded multiple state and federal agencies their first comprehensive look at the endangered species since its discovery in Illinois nearly 20 years ago near Lemont and Lockport. The finding could have thwarted plans for the 12.5-mile, $738 million road linking Interstate 55 near Bolingbrook to Interstate 80 near New Lenox. The project concludes in November after nearly a decade of stalls.

As part of agreements that allowed the construction of I-355 to proceed, the dragonfly gets a slim chance at thriving again.

Preservation efforts include raising larvae, reintroducing them to the wild and creating a Hine’s habitat from scratch. There also will be attempts to obtain genetic blueprints of the various populations to gain understanding of their peculiar habits.

Overseeing the plans are Soluk, who’s a University of South Dakota professor of aquatic ecology, and a team of eight graduate students hired by the Illinois State Toll Highway Authority.

Soluk pays homage to the Hine’s by wearing a T-shirt with the bug’s scientific name: Somatochlora hineana.

“There probably were lots of these guys up and down the Des Plaines River valley. Now there is nothing left,” he said. “We are trying to recreate what once was.”

Like most dragonflies, the Hine’s needs marshes and wetlands for feeding and mating. But land near the Des Plaines River doesn’t offer your typical marshes and wetlands.

From below the river’s bluffs, dense patches of cattails grow as tall as 10 feet, vines of purple morning glory snake upward along the reedy stalks. The mystery of the dragonfly can be found near the roots, in water that appears in the cattail shadows as ordinary puddles.

The first indication of something unusual about the water is its temperature. It’s cold. It’s a classic sign of a marsh fed by natural springs, the never-ending flow of water cleansed by limestone bedrock mere feet below the surface. The rare conditions are necessary for the constant nourishment the Hine’s needs during the four to five years it passes from egg to larva to adult – one of the longest life cycles for any dragonfly species.

Hine’s larvae find refuge in the crawfish burrows that remain moist during droughts. Considering crawfish are known to eat the larvae, this is an odd relationship.

“It is a great place for them to go in the summer,” Soluk said. “The not-so-great thing is they don’t have a great house companion. They will get eaten.”

Most of the dragonfly’s population is believed to be restricted to forest preserves at DuPage County’s Waterfall Glen, Cook County’s Black Partridge and Will County’s Keepataw and Lockport Prairie.

The dragonfly was declared an endangered species in 1995. Besides Illinois, the only known places left for the Hine’s are parts of Missouri, Michigan’s Upper Peninsula and Wisconsin’s Door County, where the population numbers in the tens of thousands.