Based on two compression fossils from the Middle Jurassic Jiulongshan Formation of Daohugou Village, Ningcheng County, Inner Mongolia, China, a new fossil species, Poljanka curticapillata L, Luo & Yao, sp. nov., of the extinct family Protopsyllidiidae is described. It is characterized by the flagellomeres 16 slender and 6 small subsections at apex, the presence of genae, the basal tarsomere almost equal to the apical tarsomere of fore and middle legs, and basal tarsomere about 2.11 times as long as apical tarsomere of hind leg, and the forewing veins R longer than M + Cu1, Cu1 with curved Cu1a and Cu1b, and Cu1a/Cu1b ratio 3.463.63. These body features and combination of forewing venation characteristics differ the new taxon from all other known species of Poljanka Klimaszewski, 1995. We also provide a key to the species of Poljanka and revise the diagnosis of the genus.