Key to the Palaearctic species of the genus Hercostomus Loew (Diptera, Dolichopodidae) 3. Part. Cesa News 78: 1-6. Key of species of the third part (femur yellow, postocullar bristles black) of the genus Hercostomus Loew is composed for Palaearctic Region. For the first time, 16 species are added in this key: Hercostomus flaviventris Smirnov et Negrobov, Hercostomus nemorum Smirnov et Negrobov, Hercostomus beijingensis Yang, Hercostomus gansuensis Yang, Hercostomus wudangshanus Yang, Hercostomus xiaolongensis Yang et Saigusa, Hercostomus acutangulatus Yang et Saigusa, Hercostomus leptocercus Stack., Hercostomus klowdeni OlejnÃÄek, Hercostomus silvestris Pollet, Hercostomus blankaartensis Pollet, Hercostomus helvеticus Pollet, Sybistroma setosa Schiner, Sybistroma nodicornis Mg., Ludovicius sinaiensis Grichanov, Ludovicius miricornis Parent.