Scorpions glow under ultraviolet (black) light.

Three species of scorpions are commonly found in the Arizona Upland subdivision of the Sonoran Desert. They are the bark scorpion, Centruroides exilicauda, the striped tail or devil's scorpion, Vaejovis spinigerus, and the giant or desert hairy scorpion, Hadrurus arizonensis.

Although more than 30 species of scorpions are found in Arizona, only the sting of the bark scorpion is considered to be truly life threatening. Its slender shape, and its long, delicate pincers and tail distinguish it from other more stoutly-built species in the state. Of the three most commonly seen species, the bark scorpion is the only one that prefers to climb, and it may be found many feet above the ground on trees and rock faces. Because bark scorpions display negative geotaxis, that is they orient themselves upside down, people are often stung by them as they pick up an object and press against a scorpion clinging to the underside. Defensive stinging is usually a series of quick jabs, after which the scorpion makes a hasty retreat.

Source
desertmuseum.org