radial cell open at apex, the radialis usually represented by a along, spurious vein which tends to delimit a very long radial cell; when the cell is thus long, the marginalis is at least half as long as its distance from the basalis; if the radialis is short and the radial cell almost closed apically, then the marginalis is much shorter than its distance from the basalis and the scutellar hollow is usually of pronounced reniform appearance