“How do they get together in the first place? One theory is that individual cells congregate in one spot because of a concentration of a common food—certain bacteria, for example. We see something of this in a higher form like the ladybird beetles. They’re usually loners, but sometimes in autumn a group will be attracted to a certain bush where they feed on aphids, and then they sometimes continue as a combined group after that. They form a colony held together by chemical attractants and tactile stimuli . . .

“You folks, particularly, know the ocean’s Portuguese man-­of-­war . . .” Heads inclined in agreement, glad to be hearing a familiar name. “In these forms, several types of individuals get together to divide life functions in a crude way. In the man-­of-­war, this division of labor is actually controlled by a primitive nervous system—a ‘nerve net,’ it’s called. I am saying the Yarkie roaches may have the same morphology . . .”

Elizabeth’s voice came across the room, clear and accepting. “You mean it really wouldn’t be all that unusual if the roaches coming out of a single colony were controlled by a master brain! Not beyond a natural phenomenon!”

“Exactly,” Hubbard said. “And now you can see why I’m so anxious not to destroy anything before examining and studying this major biological possibility.”

Elias Johnson shook his large head, saying with a rueful smile, “There is something indecent in learning such important matters for the first time at my age.”

Stephen Scott’s expression said he would not believe a word of the folderol. The notion was crazier than the astronomy stuff about black holes and four dimensions spouted by the Harvard types. Any man knew that bugs didn’t have “brains,” and nothing this professor said would make him credit it!

The sheriff spoke, more to himself than to others. “Why Yarkie?”

Peter Hubbard heard him. “Who knows? You have a quiet island. The dump would be a great starting place . . .” He held his voice level. “As Dr. Lindstrom and I explained at the beginning, chemical variations can start a mutation. I mentioned ‘ENU.’ There are DNA changes that alter amino acid sequences. Some biologists have mapped the development of the races entirely on the basis of the amino acid changes in a basic life substance known as the cytochrome c molecule.”

Russell Homer’s chest swelled. This was like being in a Harvard classroom!

Amos Tarbell was frowning. The scientist was way over his head now. He said so forthrightly.

Hubbard gave them all a friendly, understanding smile. “I have gone deeper than I intended, though this is still just on the surface of what biology knows today.”

“The point is,” Elizabeth repeated, “there is absolutely nothing impossible about there being a roach world in that cave not too terribly different from ours.”

“That,” said Bonnie Taylor unhappily, “is a terribly spooky thought!”