There has been an accident, a terrible accident at the National Zoo. The caretakers at the Invertebrate House are in shock.

It seems the ants that live in a glass-fronted display case in the Invertebrate House got excited. "They may have been too ambitious," said Ed Smith, the man who cares for the leaf-cutting ants from Trinidad. "They may have gotten themselves worked up."

What the worker ants did, quite by mistake, was remove the head of their queen. Apparently, the workers were trying to transfer their egg-laying monarch from the chamber where she has resided since being shipped almost four years ago from the Cincinnati Zoo. Apparently, the hole they were trying to pull her through was small. The queen was big. Pop.

At least that's how Smith re-creates the accident in his mind. No one actually saw it happen. "Last Wednesday, one of the volunteers said, 'Hey Ed, take a look at this,' and I let out a string of expletives."

Ant specialists refuse to speculate on whether an ant can feel totally stupid. Basically, scientists think of ants as amazing little machines, driven by their genes, which act in concert with a world that they know largely through smell.

That is why an interesting thing is now happening at the Invertebrate House. The workers are still tending their queen. "They are continuing to hold her in the same position," Smith said. "As long as she still smells like the queen, they will care for her."

There her body hangs, on display, her headless thorax and abdomen suspended from the ceiling of her royal chamber, her back to the roof, her legs dangling. Or rather the two legs she has left. The other four mysteriously disappeared the same day her head did.

Where is the head? "We're not sure," Smith said. Did the workers eat it? "No," Smith said. "I don't think so." Is it on the trash heap outside the nest, where the ants deposit their dead and discard pieces of their fungus garden? "No, the head is someplace in the nest," Smith said. "And wherever it is, I am sure they are taking good care of it."

Somewhere, nestled among the legs and loving mandibles of her attendants, the queen's head is being cared for. They are probably bringing food and trying to feed the head. A guess about what they are doing with the legs would only be reckless speculation.

Meanwhile, back in the royal chamber, which is on public view and can be examined in great detail with the aid of a flashlight and magnifying glass every day of the week except Monday and Tuesday, the queen's body rests. It would be reckless speculation to infer that she misses her head.

Smith contends that among insects, heads are overrated as body parts. Indeed, the queen may have continued to lay eggs for hours or even days after her head was removed. "She seems to be doing pretty good headless," Smith said. "Heads aren't as important as you might think."

Still, removing the queen's head from her body was not a good idea, Smith admits. Sooner or later, probably in weeks, the queen's head and the queen's body will stop smelling like the queen and start smelling dead. "The bacteria will start their work," Smith said. Even royalty rots.

The colony, eventually, is a goner. A queen from this common tropical leaf-cutting species can live as long as 14 years. But without a queen, there can be no eggs. That is all a queen does. She is a virtual egg-laying machine. No eggs, no workers.

The eggs and larvae that are now being tended will probably be reared by the workers, but eventually the colony will age, and finally wind down.

At present, all seems strangely normal in the colony. "Life goes on," Smith said. As Elisabeth Kubler-Ross would put it, the ants seem to be in the denial stage. The bigger workers are still collecting the leaves that Smith puts out for them and carrying chiseled bits of greenery back to the nest, where smaller ants masticate the bits and place them in their gardens, where still smaller workers plant thin hairs of fungi, which produce spores that feed the wormlike larvae and workers.

There is, however, little chance of the colony saving itself. Smith reports there are no winged ants in the colony's brood. Winged forms are the sexual ants, the virgin queens and males. But alas, every ant in the nest now is a sterile female worker, with the exception of the headless queen, who is still full of sperm, but who is dead. Couldn't the colony turn a few of the remaining eggs into virgin queens? Yes, in fact, but there are still no males.

For the near future, Smith will watch over the colony. It could last a year. Eventually, however, the remaining ants will get tossed out on the lawn beside the Invertebrate House or be put into a freezer. A new queen and a thousand workers will be brought in from the Cincinnati Zoo, one of a handful of zoos with large ant displays, to start a new colony.

But this time, Smith will open more portals into the chamber that surrounds the queen's room. Smith believes the ants only wanted to move their queen to another room because the fungus garden that grew up around her was not as robust as the ants would have liked. In other words, the ants were only doing what they thought was best.

Nature may be beautiful, but it is not perfect. Even an ant can make a mistake, a big mistake.