Several samples of mites trapped over recent days in northern Illinois were sent to Nebraska for identification, state health officials said Thursday, spurring hopes the culprit behind a mysterious outbreak of rashes will be caught at last.

"We have collected several samples of mites. Currently, we're trying to identify them," said Kimberly Parker, spokeswoman for the Illinois Department of Public Health, the agency leading the investigation. "I'm told there are many varieties of mites and it's not an easy process to identify them."

Health officials collected mites using dozens of sticky traps set up in forest preserves and on golf courses and private, wooded land, but haven't yet pinned down an exact mite behind the mysterious bloom of rashes -- if mites are to blame at all. The samples were sent by overnight mail to a specialist in Nebraska.

"As soon as we get it, we'll try to identify them," said the specialist, James Kalisch, an entomologist at the University of Nebraska-Lincoln who co-wrote a study on a form of Pyemotes mite blamed for a 2004 rash outbreak in Kansas and Nebraska.

Once received, identification would take "not long at all," he said. The samples were expected to arrive in Nebraska Friday, Kalisch said.

As the identification process continued, state health officials sought to reassure scratching masses in the Chicago area that mites pose no known health threat beyond itchiness.

No one should change their plans for summer recreation because of the mystery, said Kitty Loewy, spokeswoman for the Cook County Department of Public Health.

Earlier this week, Cook County health officials offered advice for avoiding the mites that included wearing skin lotion, using insect repellent and wearing long-sleeve shirts and pants.

They also suggested avoiding thick weeds and heavy foliage, especially during evening hours.

As officials sought to pin down what is causing the epidemic of rashes, some area residents reported collecting samples with cellophane tape and in plastic baggies and wondered what to do with them.

At Bemis Woods, a portion of the Cook County Forest Preserve District in Western Springs, the Tribune gathered dead pin oak twigs, damp leaves, tall grass and elm sprigs, and brought them to the Field Museum.

Just upstairs from the stuffed man-eating lions of Tsavo, entomologist and collection manager Daniel Summers pulled the sprigs apart above a petri dish and soaked each handful with rubbing alcohol to wash whatever clung to its surface into the container below.

On his third petri dish, Summers hit pay dirt.

Under bright lights and 40-power magnification, the translucent mite with two reddish spots on its back seemed to shine in suspension.

In an office stacked with bookcases, cigar boxes full of moths and dragonflies, plus two stuffed birds borrowed for decoration, Summers opened a reference book and found a near-perfect match on page 377 of Hern's Medical Entomology -- a mite named Pyemotes ventricosus.

There was no way to tell if the mite under Summers' microscope was Pyemotes ventricosus, but it was almost certainly a Pyemotes, Summers said.

"A widely distributed predacious mite ... barely visible to the naked eye" that feeds on things like insect larvae and boll weevils, the Pyemotes entry in Hern's read.

"Normally beneficial, but unfortunately it also attacks man, producing a very disagreeable dermatitis."

Summers closed the trash bag holding the rest of the samples and placed it carefully on the floor.

In about a half-hour, a bright red rash with white blisters developed on Summers' right forearm -- the hand he'd been jabbing into the bag.

"All in the line of duty," he deadpanned.

Did it itch?

"Yes," he said.