That got through. The curator nodded grimly. “I’ll get moving on it right away.”
When Bram returned to Harld, the thin-featured zoologist was waiting for him next to a table spread with photoplastic readouts. He handed one to Bram without comment.
Bram took the stiff sheet from him. It showed a slender, jewellike creature with bulging metallic eyes and four fragile, veined wings.
“Odonata,” Harld said. “Suborder Anisoptera. Also known as the dragonfly, or sometimes by such names as the devil’s darning needle, the mosquito hawk, or the bee butcher.
Bram studied the photograph. He could see several features that suggested a possible provenance for the insect-folk: the domelike eyes, the long segmented body with the claspers at the end, the six wiry legs all grouped together just behind the head.
“Our neighbors across the plain don’t have wings,” he pointed out.
“Neither did their ancestors,” Harld said. “You’re looking at the adult form of the dragonfly. That creature on the dissecting table is descended from an immature form called a nymph.”
Bram looked across at the grisly specimen, the liplike structure with its hooked clasping lobes was spread out to more than a fourth of the creature’s body length. He shuddered.
“Dragonflies spent most of their lives as nymphs,” Harld went on. “Years, sometimes. They lived underwater, breathing through gills, eating voraciously till they grew to size. They’d attack anything that moved—creatures bigger than they were. When it came time for them to change, they’d climb up a reed, split their skin, and emerge as that glorious winged creature you see there. The adult form—the imago—was the one that reproduced. It lived only a few Tendays and died after laying its eggs.”
He handed Bram another photoplastic readout. This one showed a dragonfly climbing out of a pale, cast-off ghost of itself and spreading its gossamer wings.
“What confused the issue,” Harld said, warming to his subject, “was that Odonata’s like no other insect order. There was a separate evolution of the nymphal and imagal forms—probably dating back to before Earth’s Carboniferous period. The dragonfly larva lacked the specialized regeneration centers—’imaginal disks,’ they’re called—that in other insects formed the adult tissues from latent embryonic cells, while the larval tissues melted away. They never went through an intervening pupal stage. They changed by direct growth.”
He was shoving more readouts at Bram. “The nymph adapted for an aquatic life, while the adult dragonfly remained virtually the same,” he said. “The nymph evolved independently. It developed gills. Then, at some point, apparently—like other aquatic creatures—it left the water in its immature form and developed the ability to breathe air.”
Something ugly stirred in Bram’s memory, the shadow of an ancient image.
Harld was trying to show him something on the autopsy table. “Jorv was perfectly right about the way they developed the equivalent of lungs. A portion of the alimentary canal just anterior to the rectum became enlarged into a sort of bellows.”
One of the other zoologists, a freckle-faced fellow, grinned crudely. “What a way to inhale,” he said.
Harld looked annoyed. “It was an obvious evolution-dry step—that’s where the gills were, with their ready-made oxygenating apparatus. In human beings, the embryonic gill structures are derived from the upper alimentary canal—and that’s why breathing and swallowing are interrelated in us.”
The shadowy memory nagged at Bram. There had been something, a long, long time ago…
Harld was saying, “So it was through these aquatic forms that evolution got around the problem of the breathing spiracles that had formerly placed limits on the size and intelligence of land insects. Plus the modification of the exoskeleton into a partially internalized support. It gave the Odonata access to the evolutionary niche previously occupied by the large mammals.”
“And now they’re the inheritors of the earth,” Bram murmured.
Harld frowned. “But first they had to learn how to reproduce in the nymphal stage. Without having to metamorphose into the adult winged form. Because otherwise the need to fly would have placed a limiting factor on their size.”
And then Bram suddenly remembered.
“It was an unstable allele. Original Man spliced a set of synthetic chimeras into dragonfly DNA. They were trying to modify the nymph to create an organism that would keep insect pests under control in their arctic regions. They thought it would remain an aquatic form and do man’s work for him. But it got out of hand.”
“What?” The three zoologists gave their full attention. “Do you know something of this, Bram?”
It all came flooding back. It had been buried for almost seven hundred years in a mind that had become overlaid by other experiences. Slowly at first, then with increasing fluency, Bram told them about the synthetic heterochronic gene that had made the self-reproducing hen’s egg possible—about the way a DNA chimera had been contrived out of genetic material derived from the dragonfly and the axolotl. How, generations later, Original Man had discovered the dangers lurking in the construct and had radioed a warning in a codicil to his first great Message. And how the Nar, accordingly, had suppressed the file—though it contained the seeds of man’s immortality. How he, Bram, a rare human apprentice in a Nar touch group, had stumbled upon the reference and confronted his mentor, Voth, with it. How the entire Nar nation had carried their burden of guilt and finally, stunningly, made amends.
“You’re saying, then, that it was the nymphal dragonflies that exterminated Original Man?” Harld asked.
His eyes were filled with horror. He was wondering, Bram knew, if it was all about to happen again.
“No, no,” Bram said. “Original Man solved the problem. Or thought he had. At great cost. The near destruction of his arctic ecology. But the mutation must just have been biding its time. It waited, buried in dragonfly nucleotides, for forty million years … fifty million years. Long enough for the human race to go the way of the dinosaurs and to be replaced by a dominant species evolved from rats. Long enough for the rat-people to go the way of humankind—according to that timetable of periodic extinctions that your department drew up when we first arrived at the Milky Way. And when the rat-folk were gone, there was an ecological niche vacant, waiting for a new intelligent, cooperating species about the size of a man. No mammal, no vertebrate, could have competed with such as the nymphs had become.”
All of them, the three zoologists and Bram, involuntarily looked over to the dissection table where the latest inheritor of the Earth lay. Harld swallowed hard.
“Man did this?” he asked.
“No, we must not be so arrogant,” Bram said. “Perhaps it would have happened without us.”
Harld opened his mouth as if he were about to say something further. But at that moment Jao came bursting into the improvised morgue.
“Better come quick!” Jao panted. “They’re on their way!”
“Here?”
“Yar. About a hundred of those ground vehicles of theirs. We’ve got to round everybody up and get out to the shuttles before we’re cut off.”
Bram whirled around to the three zoologists. “Get going. Put on your vacuum suits and tell everybody you see to do the same. We’re going to let the air out of this place.”
He turned to Jao again. “All right, let’s start deputizing people. How many of those shuttles are ready to be flown?”
“Enough—if we jam them full of people and dump everything else. In a couple of hours we can strap pallet rockets to some of them. It won’t take much of a boost to at least get them off the ground out of harm’s way. The pilots can finish their countdowns in space if they have to.”