"Just as we would need to establish grasslands to feed our cattle, cornfields to feed our chickens, forests to provide our paper and lumber and plastics, bees to pollinate the blossoms of our plants so we can have fruits and vegetables, so must our unknown Chtorran planners need to establish the equivalent support species necessary to the survival of their civilization. That is precisely what is happening now. And will continue to happen.

"Based on a weighted Skotak-Alderson simulation, the infestation of the Earth will occur in three, perhaps four, distinct stages. Each stage will see a specific level of species support established before the next level appears. In other words, they won't bring in the Chtorran equivalent of coyotes until the Chtorran rabbits are fat, and they won't bring in the Chtorran rabbits until the Chtorran pastures are green--0r in this case, purple-and they won't plant the pastures until the Chtorran earthworms have softened the ground. That puts us at a disadvantage, because we'll be seeing each species out of context, not knowing where each one fits in the larger pattern. It'll be as difficult as trying to extrapolate the rest of the symphony, when all you have is the sheet music for the tympanist and the third trombone.

"That's why we can't give you the hard answers yet. What facts we do have are still unconnected. We can only give you the larger pattern that all the facts point to. This infestation of the Earth is their way of clearing the land. It's the easiest way to deal with the local residents-clear them out before you move in. We're supposed to be long gone before the new tenants arrive. If you'll pardon an unpleasant metaphor, what we are experiencing is the Chtorran version of a slum clearance. A neighborhood improvement project-"

She pointed to the screen behind her. It lit up with slides of the nightwalker, the millipedes, the sea sludge, the red kudzu, the stingfly, the puffball creature, the pipe cleaner bug and a whole bunch of other things I didn't recognize. Dr. Zymph said, "-and these are the shock troops- the advance men for a highly competitive ecology; these are the bugs and beasties that are intended to soften up this planet for the rest of the ecology to follow. Let me say it again: the present infestation is only the first wave of a much larger and meaner infestation still to come. What comes next are the creatures that eat these!"

She bent to her notes for a moment, frowning, then looked up at us again. Her expression was grim. "Don't be misled by those who would minimize the situation. We are not going to find any easy controls for this or later infestations. We do not have the necessary competition on this planet. We human beings may not even be competitive enough, ruthless and vicious enough, to muster the necessary effort. I hope I'm wrong. But I don't think I am." She paused a moment to let that sink in.

"We must recognize from the very beginning that our natural defenses are not going to work. Our only possible countermeasures will be developed by finding the weaknesses within the Chtorran ecology. We must discover the interrelationships of these creatures and sabotage them in any way we can. We must use this invading ecology against itself! We must start today! It will not be an easy task! It will require a massive mobilizationthe complete and total mobilization of every human being on this planet! And we must begin it immediately!"

She stopped to wipe her forehead. She was beginning to show the strain of what must have been for her a very difficult task. I was beginning to suspect something from the audience reactions around me. These delegates hadn't come here to be frightened out of their wits, but that was exactly what she was trying to do. From their continual disturbed murmuring, I guessed that they had come with the idea that they were going to be reassured that everything was under control-we just need an increase in next year's appropriations, no problem, and then we can all go home, back to our newly claimed wealth. Only it wasn't working out that way.

Dr. Zymph was talking about the end of the world. And I could see the hostility on some of the faces of her listeners.

She was saying, "-I will not try to soften this for you, because I do not think the dangers can be understated. We are facing extinction.

"We are not being invaded," she said. "Not yet.

"But-we are going to be invaded.

"How soon it will happen, we don't know. How long this phase will last, we don't know. What kind of creatures have initiated it, we don't know. What kind of creatures will appear next, we don't know. But I promise you-we will find out. If we live.

"It is inevitable. We are going to be invaded. By something. By the next level of this ecology. By the life forms that feed on these. And whatever comes, whatever form it takes, will be umpteen times more competitive-meaner, nastier and more vicious -than the things we're seeing now. What you see up there"and she pointed toward the screen again, her arm stretched up and back, her finger stabbing like a pistol at the last of her slides, the gaping maw of a full-sized crimson Chtorran-"is just a candle before the firestorm!"

And with that she was through. She did not say, "Thank you," but it was clear that she was finished. She switched off her clipboard and strode from the stage.

There was no applause.

DR. ZYMPH'S remarks had not gone over well. You could feel the resentment. The audience boiled out of the auditorium like a nest of hornets. Their voices rising shrilly, they clustered into angry knots. Small arguments were breaking out all over, some erupting into shouting matches.

"-outrageous!" fumed one little man, shoving rudely past me. He was dark-skinned, he wore an expensive suit and he had a thick Middle-East accent. "Lies and propaganda! Next we're going to be told that the only answer is a military one! But my government isn't going to buy their horror stories! They're using this as an excuse for their own rearmament-" The rest was lost in the hubbub.

"I'm telling you she did not!" A tall, bald man with glasses was surrounded by a score of other scientists. "If anything, this was the toned-down version! If there's been any misstatement in the facts, it's been on the side of caution!"

The roar and buzz of a thousand separate voices swirled in the air above the lobby. A large crowd surrounded a huge fat man and a small loud one who were alternately booming and sniping at one another-a duel between a foghorn and a magpie. I couldn't get close enough to hear what they were saying, and the spirited reactions of their listeners were drowning out the meaning, leaving only the shredded sounds of their voices.

Behind me, someone else was preaching; I turned to see a bulldozer-shaped woman backing a nervous-looking man up against a corner. "-and we have the papers to prove it! Have you read them yet? No? I'll send you copies. Marsha got a letter from the man himself, saying how impressed he was by her volume-"

I faded sideways, almost into the center of another conversation, a very quiet one. The speaker was a well-mannered black man, very soft-spoken. His listeners were a group of reporter types, each one holding his or her recorder out like a shield. ". . . The people have had enough bad news. They want to hear something good for a change. Of course, Dr. Zymph's remarks are not going to be popular-I expect to see a lot of resistance. But now let me add this. If the threat is real, you can be sure that the American people will shoulder their fair share of the responsibility. We'll handle it."

I'd heard enough. I headed out toward the lounge area. I was confused at the reaction of the delegates-didn't they realize?-and angry at them as well. I stood in the middle of them and fumed. I would have liked to have stuffed a few of them into the nearest Chtorran in full view of their colleagues. That would change some minds, all right!