marginalis distinctly longer than its distance from the basalis (Small species, ca. 2.5mm.; radial cell either open or closed but its length when closed, or as indicated by the incomplete radialis, at most but slightly greater than the length of the marginalis; seventh and eight gastral segments not clearly separated and together forming a smooth, narrow, downcurved, almost hairless segment which is closely ensheathed by the hypopygium; large sternite never humped at base (cf. Psilomma))