Genus of rather large mosquitoes (formerly known as Theobaldia) containing about 35 species. Most species live in temperate countries (e.g., C. silvestris, C. incidens). Larval habitats are usually ground regions of water with submerged vegetation. The species C. inornata, C. melanura, and C. dyari are vectors in North America for both Western and Eastern Equine Encephalomyelitis (virosis). See Nematocera.