Veined Ctenucha

Ctenucha venosa

• Content: Ned Harris
• Photo: Ned Harris

Moths ordinarily fly at night and rest with their wings in a horizontal position.

I remember well the first time I saw a Veined Ctenucha (pronounced “teh-NEW-kah”). I was out at the Arizona-Sonora Desert Museum photographing fall butterflies when this striking insect flew in and landed in front of me. Being primarily a birder at the time, I naturally assumed it was a butterfly since it was flying in the daytime. A docent happened by and I soon learned that this was actually a diurnal moth.

Butterflies usually fly by day and rest with their wings erect. Moths ordinarily fly at night and rest with their wings in a horizontal position. The antennae of butterflies are club-like ending in a swollen tip, i.e. they look like a Q-tip. Antennae of moths never end in a knob and are often feathery.

Veined Ctenucha moths have a fuzzy, scarlet head, black antennae, an iridescent blue body, and brownish black wings with discontinuous white wing fringes and three orange veins (one is branched) on the forewings. They usually keep their wings folded flat against their body, which makes them look smaller.

Here in the Sonoran Desert, adult Veined Ctenucha moths and other diurnal Ctenuchid moths are the most common in the autumn before the first frost. These small, dark moths are generally seen visiting fall-blooming flowers along with late-season butterflies. The Veined Ctenucha caterpillars are fuzzy with black and yellow stripes. They feed on the abundant late summer grasses that appear after our summer monsoon rains.

I have seen Veined Ctenucha moths several times in lower Sabino, usually in late fall. These photos were made on October 14, 2015 in lower Sabino.