On September 26, 1924, the ground collapsed beneath a truck in a back alley in Washington, D.C., revealing a mysterious underground labyrinth. In spite of wild speculations, the tunnel was not the work of German spies, but rather an aging, eccentric Smithsonian scientist named Harrison Gray Dyar, Jr. While Dyar's covert tunneling habits may seem far-fetched, they were merely one of many oddities in Dyar's unbelievable life.

For the first time, insect biosystematist Marc E. Epstein presents a complete account of Dyar's life story. Dyar, one of the most influential biologists of the...