Morphology and DNA barcodes confirm a new chironomid species within the Rheocricotopus (Psilocricotopus) orientalis group (Diptera: Chironomidae). Rheocricotopus (Psilocricotopus) kongi Lin et Wang sp. n. is described and illustrated based on adult male from Hainan, China. Key to adult males of the R. orientalis group is given.
Keywords: Diptera, Taxonomy, COI, Orthocladiinae, key, China.