The family Mesopsychidae Tillyard, 1917 presently consists of ten described genera from the Early Permian to the Early Cretaceous of Australia, China, Kyrgyzstan, Russia, South Africa, Tajikistan, and Ukraine. Herein, a new genus and a new species of fossil mesopsychid, Epicharmesopsyche pentavenulosa gen. et sp. nov., is described from the Middle Jurassic Jiulongshan Formation of Inner Mongolia, China, supplementing the family-level diversity. The well-preserved, new material reveals many characters, including antennae, wing venation, shape and genitalia that increase our morphological understanding of the family, although unfortunately the mouthparts and most of the legs are not preserved. Diagnosis of the Mesopsychidae is emended to include a four- or five-branched MP in both the fore- and hind wings. This is the first documentation of a wing coupling structure in the Mesopsychidae, consisting of three to four frenula bristles on the humeral lobe at the base of the costal margin of both hind wings. Asymmetrical shape and size of the left and right wings on a specimen of E. pentavenulosa gen. et sp. nov., seems to be a common condition for mesopsychid taxa from northeastern China.