Showing somewhat more restraint and considerably more dignity, Birdie nibbled the corner of a French fry, then sat, extended one hind leg, and diligently cleaned between his toes.

Cat and dog were sleeping when Ted Springer cal ed from Columbia at eight.

“Microbiologists put in a long day,” I said.

“I was running some samples. Listen, I found the file on your Lancaster skeleton and there may be something.”

“That was quick,” I said.

“I got lucky. How much do you know about the amelogenin locus?”

“Girls show one band, boys show two, one the same size as the ladies, one slightly larger.”

“B-plus answer.”

“Thanks.”

“Amelogenin appears as two bands on a gel, but there’s one nifty little variation not everyone recognizes. With normal males, the two bands are of similar intensity. You with me?”

“I think ‘normal’ is going to be the operative word,” I said.

“With Klinefelter’s males, the band representing the X chromosome is twice as intense as that representing the Y chromosome.”

“Klinefelter’s males?” My brain was grinding, refusing to shift into gear.

“The XXY karyotype, where there are three sex chromosomes instead of two. My col eague didn’t pick up on the intensity difference.”

“The unknown had Klinefelter’s syndrome?”

“The system’s not one hundred percent.”

“But KS is a good possibility in this case?”

“Yes. That help any?”

“It just might.”

I sat motionless, like a hunting trophy that’s been stuffed and mounted.

Klinefelter’s syndrome.

XXY.

A bad rol of Slidel ’s embryonic dice.

Booting up the computer, I began surfing. I was working through the Klinefelter’s Syndrome Association Web site when Boyd nudged my knee.

“Not now, boy.”

Another nudge.

I looked down.

Boyd put a paw on my knee, raised his snout, and snapped at the air. Gotta go.

“Is this on the level?”

Boyd dashed across the room, spun, snapped, and twirled the eye hairs.

I checked the time. Ten-fifteen. Enough.

Kil ing the computer and lights, I headed for Boyd’s leash.

The chow danced me out of the den, thril ed at the prospect of one last sortie before bedding back down.

The darkness in the annex was almost total, relieved only by heat lightning flickering through the trees. Inside, the mantel clock ticked. Outside, moths and June bugs fought the windows, their bodies making dul , thudding sounds against the screens.

When we entered the kitchen Boyd’s demeanor changed. His body tensed, and his ears and tail shot up. A short growl, then he lunged forward and began barking at the door.

My hand flew to my chest.

“Boyd,” I hissed. “Come here.”

Boyd ignored me.

I shushed him. The dog kept barking.

Heart pounding, I crept to the door and pressed my back to the wal , listening.

A car horn. June bugs. Crickets. Nothing out of the ordinary.

Boyd’s barking was becoming more urgent. His hackles were up now. His body was rigid.