The results of our studies on the Brazilian family Serritermitidae are presented here. Microsculpturing is simple and consists of a few rows of small, tongue-shaped papillae on the anterior and posterior wing margins and a few rows of angular arrowheads in the anterior one-third of the wings. Hairs are almost absent, a few small ones being scattered on some of the veins. The bearing of wing microsculpturing on the phylogeny of the Serritermitidae is discussed. It is concluded that the family arose as a lone sideline from the common ancient rhinotermitid stock. The other line from this stock gave rise to the Stylotermitidae on the one hand and the Rhinotermitidae on the other.