Wing membrane without macrotrichia, occiput without row of strong setae. Palpi short. Eyes bare. Face wide. Stem of M and M2 absent. RS base distinct. Crossvein r-m meets M3+4 and CuA stem. CuA gently curved. Abdomen insertion broad. Fore tibiae shorter than femora.
The following apomorphic characters refer the genera Plesiognoriste and Protognoriste to the Lygistorrhinidae: short palpi; small dorsal cleft of anepisternum; anepisternum and metepimeron not divided by laterotergite (possibly plesiomorphic); short, incomplete Sc; short R1; RS base and M stem reduced; r-m horizontal and fused with R5; hind coxa smaller and broader than mid coxa; abdomen insertion narrow; cerci simple. Face wide, with three ocelli, situated almost in straight line, suggestive of Manotinae, but structures of palpi, katepisternum and metepimeron, and absence of strong setae, show no apomorphies with respect to that subfamily. Eye size, face width, vein vestiture, tibial spurs of equal size, and complicated shape of the gonostyli are more primitive conditions than occur in Recent lygistorrhinids, although some features of venation and gonostyli are apomorphic. The short fork of M3+4 and CuA and absence of a long proboscis are most similar to the genus Seguyola Matile. It is possible that these two genera should be treated as a separate subfamily of Lygistorrhinidae.