Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Euclidia diagonalis is a moth of the Noctuidae family. It is found in North America, including Arizona and New Mexico.The wingspan is about 28 mm. A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth (about ten times the number of species of butterfly), with thousands of species yet to be described.