One new genus and species of Ithonidae, Cretithone zhangi gen. et sp. nov., is described from the mid-Cretaceous Kachin amber. Cretithone gen. nov. is distinguished from other fossil ithonids by the combination of the following characteristics: exceptionally broad costal space; proximal branches of RP fused into a single vein and then fused with M; medial branches of RP fused with each other; simple basal M, with marginal forks; CuA divided into two main branches, the anterior branch with posteriorly directed subbranches and the posterior branch with anteriorly directed subbranches; and most proximal branches of CuP fused with adjacent branches. The new genus and species has been assigned to the Principiala genus-group by the fusion of the proximal branches of RP and the peculiar configuration of M and CuA. Variations in the forewing characteristics among the fossil ithonids are briefly discussed.