Comprehensive DescriptionRead full entry
General DescriptionA medium-size (3.4-3.7 cm wingspan) pale grey-white moth. The forewings are light chalky grey or tan, almost white, with a few scattered black scales. The transverse lines are reduced to a prominent black mark where each would meet the costa, with the postmedian line also indicated by a series of small spots or dashes at the veins. The orbicular spot is reduced to a few black scales or a small spot, and the reniniform is a prominent, black doubled spot. The terminal line is a series of small black triangles, and the fringe is light grey-white. The hindwings are bright white with a dark discal mark, sooty brown scales lining the veins, and a white fringe. Pale specimens of E. spumata and E. tronella lack the prominent dark spots at the costa, and are light tan, not grey. Most likely to be mistaken for Agrotis vetusta, which is larger and lacks the dark scaling at the reniform spot. There are also excellent genital characters that will separate catenula from similar species. Catenula belongs to the subgenus Euxoa. Keys to the subgenera and species of Euxoa, along with illustrations of both sexes and their genitalia, are available in Lafontaine, 1987.