Photo-Illustration: Mark Harris In Octavia E. Butler’s novelette “Bloodchild,” a quantum of humanity fleeing Earth finds sanctuary on a distant planet—but at a price. The native Tlic, a species of intelligent, centipedelike aliens, establish the Preserve, where humans can work, marry, and raise children without interference; in return, some humans are implanted with eggs by Tlic females, whose larvae must feed on living flesh. First published in Asimov’s Science Fiction in 1984, “Bloodchild” won Butler the Nebula, Hugo, and Locus Award for Best Novelette—a sci-fi Triple Crown. Narrated by a young human host who begins to question the whole arrangement...