Large-winged blattoids of the Middle to Late Pennsylvanian reveal a striking appearance, diversification, and decline in fossil record. Among them, families Necymylacridae Durden, 1969, Gyroblattidae as well mylacrid genus Opsiomylacris exhibit, largest pre-Cenozoic with forewing lengths up 7.5 cm. As finds from coal-bearing sedimentary basins Europe, North Africa, America indicate, these giant...