While trekking through the Peruvian rain forest, an eight-hour boat ride from the nearest jungle settlement, biologist Aaron Pomerantz saw what seemed like tiny invisible jets zipping across the trail. “I was out there with a net trying to catch things,” he says, “and these just changed direction and vanished.” It was his first close encounter with clear-winged butterflies, insects that inhabit Central and South American forests and have a remarkable means of camouflage: see-through or “glass” wings that make them particularly hard to spot in the dense understory. “It’s…
