Timarcha is a genus of leaf beetles in the family Chrysomelidae, with more than 100 described species in three subgenera. The most widely known species is T. tenebricosa, the bloody-nosed beetle. All species are black, wingless organisms. Timarcha are herbivorous species, living mostly on plants belonging to Rubiaceae and Plumbaginaceae, although a few can feed on Brassicaceae and Rosaceae. Timarcha is the only member of the tribe Timarchini.
