Limnebius has a worldwide distribution with more than 150 described species and 21 of them from Turkey, four of them are endemic for the Turkish fauna. Limnebius species are small water beetles which their morphologies are very uniform with oval and drop-like body shape. For this reason, taxonomists use male sex organs called aedeagi for classical taxonomical identification of Limnebius species. Molecular techniques have been widely applied in many disciplines of biological sciences including insect identification. These techniques improved over traditional morphological identification and allowed timely and unambiguous identification of insects. The enzyme cytochrome c oxidase is a large trans membrane protein complex found in mitochondrion of eukaryotes and bacteria, and cytochrome c oxidase 1 is the main subunit of the cytochrome c oxidase complex (COX 1).