Back in my footloose twenties, I lived for a year in Costa Rica, where I worked at a school in the central highlands and worked even harder, by reluctant necessity, at overcoming my lifelong horror of crawly things. Before the Costa Rican tourism board comes after me, I will say, in defense of that part of the world, that I have never lived anywhere else so ecologically magnificent. Every day, I commuted to work on a trail lined with ferns and bromeliads and the enchanted fortresses of strangler figs, while twotoed sloths lolled overhead and butterflies as big as greeting cards opened their dull-brown wings to reveal a blue as brilliant as the cloak of the Virgin Mary. At night, the moon cast shadows of avocado trees along the dirt roads, and the stars amassed in layers a billion deep. There were volcanoes, there were waterfalls, there were three kinds of monkeys, there was a dry season and a wet season and in between them an entire rainbow season, as if the local weather had been designed by Lisa Frank. On clear days, I would look out over verdant folds of mountains to where the sun glinted off the Pacific Ocean and reckon myself pretty much in paradise.

Still, there is a snake in every garden-though it was not the nation's infamous pit vipers that scared me. Before taking the job, I had not appreciated the biological coördinates of Costa Rica: south of the Tropic of Cancer, north of the Tropic of Capricorn, right in the middle of the Arthropod Zone. Once I got there, however, this fact became appallingly unignorable. My roommates in my new house included ants that looked like "Star Wars" extras, beetles that looked like U.S. Army-issue vehicles, and scorpions that unfortunately looked exactly like scorpions and made themselves at home in my sock drawer.