''Ctenucha rubroscapus'', the red-shouldered ctenucha moth, is a

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

of the family

Erebidae The Erebidae are a family of moths in the superfamily Noctuoidea. The family is among the largest families of moths by species count and contains a wide variety of well-known macromoth groups. The family includes the underwings ('' Catocala'') ...

. It was described by

Édouard Ménétries Édouard Ménétries (Paris, France, 2 October 1802 – St. Petersburg, Imperial Russia, 10 April 1861) was a French entomologist, zoologist, and herpetologist. He is best known as the founder of the Russian Entomological Society. Ménétries w ...

in 1857. It is found in western North America, where it is limited to low elevations west of the Cascade Mountains, south of

Chehalis Chehalis may refer to: People * Chehalis people, a Native American people of Washington state **Lower Chehalis language **Upper Chehalis language * Sts'Ailes people (Chehalis people), a First Nation in British Columbia * Chehalis First Nation, Bri ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

. The habitat consists of coastal grasslands adjacent to the ocean, as well as wet boggy meadows and wet prairie. The length of the forewings is 19–20 mm. Adults are brilliantly coloured black, blue and orange. Adults are on wing from late June to September in one generation per year. It is a day-flying species. The larvae feed on

Poaceae Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

and

Cyperaceae The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' w ...

species, including species of the genera ''

Dactylis ''Dactylis'' is a genus of Eurasian and North African plants in the bluegrass subfamily within the grass family. ''Dactylis'' is native to North Africa, they are found throughout the world, and are an invasive species. They are known in Englis ...

'' and '' Elymus''. The larvae are black and densely covered with short tufts of white hairs.''Pacific Northwest Moths''
/ref> Red-shouldered Ctenucha Moth

References

rubroscapus Moths described in 1857 {{Ctenuchina-stub