Junction of the genal and the hypostomal carinae. a, b genal carina meets the hypostomal carina clearly above the base of the mandible (a D. blanda; b D. rubidatae) c genal carina meets hypostomal carina clearly above the base of the mandible, occipital carina obliterated close to the junction (D. tenuis) d, e genal and hypostomal carina distinctly raised, their junction forming a lopsided triangular pyramid (d D. mercator e D. aurita) f genal carina meets the hypostomal carina at the base of the mandibles (D. flagellator). Genal index = distance between the base of the mandibles and the junction of the genal and hypostomal carina (green bars) / the basal length of the mandibles (blue bars). Scale bars: 0.25 mm. https://doi.org/10.5281/zenodo.6362512.