Carnus is a genus of flies (Diptera) with 5 described species, all of which are parasites of birds.

[3] The adult flies locate a suitable host nest, then shed their wings and feed on the blood of the developing nestlings.

[4] Mature female flies lay their eggs in the nest, where their larvae develop on organic detritus.

[4] In 2014, C. orientalis was reported for the first time in Japan, parasitizing nestlings of the Ryūkyū scops owl, Otus elegans, a new host species record.

[8] This article related to members of the muscomorph flies superfamily Carnoidea is a stub.