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.
Below each eye is a cheek area (gena), often divided into an anterior and a posterior part, while a distinct chin-sclerite (gula) is often developed behind the mouth.
S8, Sclerite between 7th and 8th G, Anterior, and g, pos S9, 8th Sclerite.
Pmst, The promesosternal sclerite or chitinous plate, unpaired.
Opisthosoma without trace of appendages; its posterior somites narrowed to opistho form a movable tail for the support of the post - anal sclerite, which has no poison glands.
Post - anal sclerite modified as a long, many-jointed feeler.
Post-anal sclerite short and undivided.
An, Orifice within which the caudal a, Movable (hinged) sclerite (sosegments are withdrawn.
A fact of special interest in regard to them is that the genus Poliochera, from the Coal Measures, appears to be a member of the same group. The name Cryptostemma, given to the first-known genus of the order, described by Guerin-Meneville, refers to the supposed concealment of the eyes by the movable cephalic sclerite.
- Integument hard, strengthened by a continuously chitinized dorsal and ventral sclerite.