Semagystia witti is a moth in the Cossidae family. It was described by Yakovlev in 2007. It is found in Afghanistan. The length of the forewings is about 12 mm. The marginal zone of the forewings is light grey with small dark spots at the veins at the margin. From the base to the postdiscal area is darker and contains brown-grey areas. The hindwings are grey-brown.