The C-band, or costal band, extends from the base of the wing along the anterior margin to the apex of vein R₁. The S-band extends obliquely from the base of cell cu₁ across r-m, reaching the anterior wing margin in cell r₁, then following the anterior margin to the wing apex. When the C-band and S-bands are connected along veins R₂₊₃ or R₄₊₅, they are usually separated along the costa by a basomarginal hyaline spot in cell r₁, immediately distal to the apex of vein R₁.