Cephalic shield continuous with dorsal integument; no shell; ctenidium projecting from mantle cavity.
These are likely to have been produced by the ripe genital glands, which may have extruded their products directly through the membranous integument of the under side.
A remarkable cord of cells having a position just below the integument occurs on each side of the head.
In this it remains until the completion of the transformation into the sexually mature insect, which then emerges from the case, leaving the pupal integument behind.
The surface of the neck is covered by integument forming the floor of the branchial cavity.