Huh? You said what about the 17-year cicadas?

Oh, they're loud, you say.

Well, don't bother telling Marian Farabee, who probably can't hear you anyway. Her backyard cicadas are so intense, she jams earplugs into her ears before venturing outside to garden.

"It's like Harleys," says the Columbia resident. "A few start up, then all of a sudden, they all start up and kind of roar."

Or Kevin Dietz, who unsuccessfully tried to drown out the sound of the little devils in his Rodgers Forge apartment by cranking up his television.

"It's the only thing you can hear. It sounds like I'm living in the Amazon," says Dietz.

Yes, ears are ringing all over Baltimore as male 17-year cicadas from Brood X break their silence -- and, incidentally, a few public noise regulations -- in an earsplitting effort to land a mate.

These high-decibel pleas pack enough sonic punch to overpower lawn mowers, truck traffic and the crackle of walkie-talkies. They're forcing some softball players to holler for pop flies and homeowners to miss phone calls.

One of the long-standing scientific mysteries surrounding cicadas is how a shrimp-sized insect manages to belt out such songs. It has only been in the past decade that a small group of biologists has begun to piece together the puzzle.

Cicada songs begin inside a pair of drumlike organs -- tymbals -- on either side of the male insect's abdomen. When the cicada wants to sing, it tenses a muscle attached to each tymbal, distorting the structure much the way a soda can dents when poked with a finger.

This buckling produces a pulse of sound, which travels into an large air sac in the insect's abdomen. The pressure generated by the tymbal pulse is powerful: "roughly equivalent to that generated by a grenade exploding one meter away," writes zoologist Henry Bennet-Clark of Oxford University in a 1998 Scientific American article.

But the real secret to the cicada's sonic punch, Bennet-Clark and others have found, stems from an unusual source: the insect's ears.

A pair of thin eardrums on the abdomen are designed not only for hearing but for amplifying sound waves reverberating in the insect's air sac. When cicada song leaves the eardrums, it's roughly 20 times louder than the clicks produced by the tymbals, scientists have found.

How loud?

Taking measurements

That's what state entomologist Gaye Williams and colleague Ben Pagac, an entomologist with the Army at Fort Meade, tried to find yesterday.

Driving through a leafy Bowie neighborhood with a Quest Technologies Model 2900 hand-held decibel meter, they piled out in front of a ranch-style house on Stonehaven Lane. Two big white ash trees stood in the front yard, alive with cicadas.

The insects, which clung to many of the leaves, were so loud they were audible even with the car windows rolled up. Williams checked her earplugs as she climbed from the car. Otherwise, she says, "it's painful after three or four minutes."

Brood X is composed of three species of cicada, each with a distinctive call, explains Williams.