You’d never know it by looking at the dragonflylike adult antlion, but its wingless larvae—fingernail-size eating machines with huge, poison-filled jaws—build deadly sand traps to capture tiny insects, including ants. Now, scientists know precisely how they do it: As the hapless prey falls into its pit, an antlion at the bottom uses its head to fling a blizzard of sand grains up the funnel-shaped slope, creating a minilandslide that pulls the unfortunate insect to its doom. The pits, scientists say, are feats of engineering—and physics.