Allantus cinctus is a species of sawfly in the Tenthredinidae family.This species is widespread in Britain, and is one of several similar carnivorous species. This species has large, asymmetrical jaws, and is often found on umbellifers where it hunts other insects. This species has a black head, thorax and abdomen, but the abdomen has two pale bars running across it. The legs are black and yellow. The wings are transparent, with a brown marking near the edge of the forewing.