An, Orifice within which the caudal a, Movable (hinged) sclerite (sosegments are withdrawn.
The palpi and probe or hypostome are attached to a movable sclerite or horny plate called the capitulum.
The glands occur in groups, and lead into common ducts which open usually so much reduced that the foremost apparent ventral sclerite of the abdomen represents the third sternite.
Post-anal sclerite short and undivided.
Post - anal sclerite modified as a long, many-jointed feeler.
Pmst, The promesosternal sclerite or chitinous plate, unpaired.