A new dustywing genus and species, namely Cretaconiopteryx grandis gen. & sp. nov., from the mid-Cretaceous amber of Myanmar is herein described in the lacewing family Coniopterygidae. The new genus is distinguished from all other dustywing species by the combination of following morphological features: relatively large body-size, comparatively rich crossvenation, origin of RP+MA near wing base in both fore- and hindwing, forewing RA and RP terminally fused into a loop, and proximally zig-zagged forewing CuP. A new subfamily, Cretaconiopteryginae subfam. nov., is erected based on this spectacular new genus. The new subfamily might represent the basalmost lineage of known coniopterygids.