Catocala caesia is a moth of the Erebidae family. It is found in the mountains of south-eastern Arizona and south-western New Mexico, and southward through the Sierra Madre Occidental in Chihuahua. The adjectival name caesia is based on the Latin root caesi, referring to the bluish-gray color of the forewing. The Bluish-gray Underwing is suggested as a vernacular name. The length of the forewings is 22.4 mm for males and 25 mm for females.