Thousands of ants are roiling gleefully in our bathroom trash basket; they're gorging on the soggy carcass of my wife's discarded tampon.

I lift the dry white string that's attached to the teeming mahogany blob. I escort the swarm to our bedroom. I yell, "Meaghan! This belongs in the toilet!"

My wife's conversing on the telephone; pointing at it, she hisses: "It's my mother!"

"Sorry!" I backpedal. "Tell her I said 'Hi!'"

Ants are leaping on my fingers now, waving clots of menses blood between their mandibles.

I carry the nasty brood to the toilet; I drown them all, like the Titanic.

"Fuck off ants! If you eat the womb lining of my wife, you die!"

When Meaghan gets off the phone, she rushes up to me: "My Mom says I'm part Indian!" she gushes.

"No way! Impossible!" I reply.

She's blonde, she reads Foucault, she hates ethnic clothes...

"You're an Indian? How?"

Her recently deceased grandfather had revealed in his will that he was not 100 percent Irish, like he always claimed. His mother was 50 percent Cherokee. Grandpa hid this fact because there was prejudice against Indians when he was young.

"Makes sense," my wife says. "He couldn't drink like an Irishman."

"Cool story!" I grin. "I studied Indians in Anthro..."

"Let's go to a Pow-wow!" Meaghan gurgles. "There's an 'ALL TRIBES GATHERING' in San Pedro tomorrow!"

Staring at her now, I see higher cheekbones, epicanthic eyes. How could I never have noticed?

"It's your period!" I chuckle, pretentiously. "You're taboo! Indians isolate menstruating women. They regard them as unclean, with dangerous powers."

"You're stupid!" she scoffs. "Indians will welcome me; they're my people."

I yank some old textbooks off my shelf, to bolster my point.

"Menstrual fluid pollutes the world," I laugh, paraphrasing page 371 of Harold Driver's Indians of North America.

"Tribes will cover you with a blanket!" I cackle, perusing James Frazer's, The Golden Bough, page 599.

"You're forbidden to pound acorns, enter sweat lodges, attend ceremonies, or mingle with hunters or shamans," I chortle, narrating the Smithsonian's Handbook of North American Indians, and Oglala Women by Marla Powers.

"You'll break spears and arrows if you step over them; you'll screw up medicine bundles!"

Meaghan squints stubbornly.

"I'm going to the Pow-wow!" she insists.

The next day, we drive to the huge anti-Columbus celebration. We park in a dusty lot next to cars with bumper stickers proclaiming tribal affiliation with Blackfeet, Pomo, Mohawk, Sioux, Navajo...

"What'd I tell you?" I crow triumphantly, as we get in line to buy tickets.

A huge hand-painted sign looms before us. It says: "WOMEN. IF THIS IS YOUR MOONBLOOD TIME, PLEASE DO NOT ENTER OUR SACRED GROUNDS. YOUR MAGIC IS STRONG NOW, IT WILL RUIN OUR CEREMONIES."

Meaghan flushes deeply, way beyond red skin.

"My feminist sensibilities are offended!" she glares.

"How'll they know?" I shrug. "Just don't tell them."

"I won't hide in shame!" she snarls.

When we reach the Arapaho man selling tickets at the entrance, my wife says, "Hi! My vagina is bleeding!"

The Arapaho points at the sign, and shakes his head.

Meaghan dives in: "Indian ladies bleed because they have wombs that little Indian boys come from! You came from a womb yourself, Indian man -- you drank menstrual blood for nine months and you were happy to have it!"

The Arapaho fidgets in his moccasins, as my wife continues: "I'm a Cherokee with a bloody Cherokee uterus! You're excluding me? And your mothers, sisters, daughters, wives? We suffer childbirth pain -- and you thank us, with this?"

Meaghan turns now, to address the gathering mob: "Where are the women's ceremonies? I want songs and dances for girls straddling maxi-pads! Maidens impaled with tampons! Widows absorbed with sacred sponges!"

The Arapaho suddenly receives reinforcements. Three men with unyielding eyes.

I pull on my wife's arm.

"Let's go, honey."

She screeches, "Patriarchy! Misogyny!"

Then she starts to cry -- huge tears of grief.

When we get home, I give her a white T-shirt. I say, "You should do some finger-painting with your moonblood."

A revengeful smirk envelops her face. Using her fingers as a brush and her menses as ink, she paints a huge, bloody vagina on the white T-shirt.

She's going to wear it to the next Pow-wow.

Hank Hyena is a columnist for SFGate.com and SF Metropolitan, and a frequent contributor to Salon.