1925 ] External Anatomy of Head and Abdomen of the Roach 197 
described. In some insects a clypeal (or clypeofrontal) suture 
extends from one frontal pit across to the other to demark the 
posterior limits of the clypeus, but this suture is absent in many 
Orthopteroid insects. Each poster o-latereal angle of the clypeus 
bears a cup-like depression, the clypeotheca or ^ pre coil a” cth of 
Figs. 5 and 4, into which is received an articulatory process of 
the mandible labelled g in Figs. 5 and 4. I formerly (Crampton, 
1921) used these points of articulation of the mandibles with the 
clypeus, as landmarks for demarking the posterior limits of the 
clypeus; but it is preferable to use the frontal pits fp for this pur- 
pose, as suggested by Yuasa, 1920. 
If we remove the labrum and clypeus and examine their inner 
or pharyngeal surfaces, the membranous lining is seen to form an 
area called the epipharynx bearing the labels pre and poe in Fig. 
8. The anterior portion of the epipharynx or preepipharynx pre 
is slightly more pigmented in the median region, and on each side 
it bears a lateral series of sense organs (only the left hand ones are 
shown in Fig. 8). The posterior portion of the epipharynx, or 
postepipharynx poe is located in the clypeal region and contains 
two epipharyngeal sclerites which are somewhat more deeply pig- 
mented than the rest of the membrane of this region. Between 
the anterior epipharyngeal region in the labium, and the posterior 
epipharyngeal region in the clypeus, are the tonne tor or thicken- 
ings (one on each side) which serve to demark the labium from 
the clypeus “internally,” and are therefore useful land-marks. 
Behind the clypeal region eps of Fig. 5 is the frontal region or 
frons fr, which is limited anteriorly by the suture (or by an imag- 
inary line when the suture is absent) extending from one frontal 
pit fp across to the other. The frontogenal (suborbital) sutures 
fgs demark the frons from the gen* ge postero-laterally, and 
the anterior arms of the epicraneal suture frs demark the frqns 
posteriorly. The epicranial suture is very faint in adult Peripia- 
netas, and is therefore represented by a dotted Y-shaped line in 
Fig. 5. The arms of the epicranial suture which form the frontal 
suture frs (demarking the frons posteriorly) extend to the clear 
spaces ofn or ocellar fenestrse which contain the lateral ocelli and 
usually remain clear or colorless when the lateral ocelli become 
atrophied. The scar-like area or frontal myocicatrix me, near the 
