70 Annals Entomological Society of America  [Vol. XIV, 
clypeal suture has ‘‘faded out,’’ leaving no line of demarcation between 
the regions “pe” and “‘fr.’’ Anterior prolongations of the arms of the 
frontal suture ‘“fs’’ have extended forward into the clypeal region and 
have marked off a paraclypeal or lateroclypeal region “pcl’’ on either side 
of the median region of the postclypeus ‘‘pe.’’ Comstock and Kochi, 
1902, call the paraclypeal regions ‘‘pcl’’ the “antecoxal pieces of the 
mandibles;” but they are no more closely associated with the mandibles 
than are the lateral regions of the clypeus in any other insects, and the 
clypanguli or postero-lateral angles or lobes of the clypeus, which 
frequently bear the articulatory areas with which the dorsal condyles 
(epicondyles) of the mandibles articulate, are very much the same in 
Raphidia (Fig. 41), as they are in any other insect. The antero-ventral 
arms of the tentorium frequently extend forward to a point at or near 
the clypanguli. In the water bug Belostoma (Fig. 76) the lateral areas 
labeled ‘‘pcl?’’ which are here referred to as the jugum, (following 
a suggestion by Dr. Parshley) are possibly homologous with the para- 
clypeal areas of the Neuropterous larve shown in Figs. 41 and 42, 
“pel; but this point has not been definitely established. 
Like the labrum and clypeus, the frons is a median unpaired region 
of the head (the posteriormost of the dorsal unpaired areas), and it also, 
according to Riley, 1904, arose from the protocerebral segment of the 
embryo. The frons, labeled ‘fr’ in all Figures, extends from the 
clypeal suture (or a line drawn between the bases of the mandibles) 
to the frontal suture, labeled “‘fs’’ in Figs. 32, 36, etc., the frontal suture, 
when present, serving to demark the frontal region. When the frontal 
suture is absent, 1f a line be drawn across from the top of one antennal 
fossa to the other, and at either end of this line an angle of forty-five 
degrees is constructed the sides of the isosceles triangle thus formed, 
correspond in a general way to the frontal suture, which is formed by the 
arms of the Y-shaped epicranial suture (i. e., ‘‘cs”’ and “fs” of Figs. 
32, 36, 40, etc.) when the latter is present. The frons usually includes 
the area bearing the median ocellus, but this is absent in many insects. 
The frontal suture ‘fs’? may extend forward ‘‘inside’’ of (or mesal 
to) the bases of the antenna, as in Fig. 32 (a condition typical of many 
larval insects); or it may extend “‘outside”’ of (lateral to) the bases of 
the antenne, as in the earwig shown in Fig. 36. In most larve (Figs. 
32, 40, 79) the frontal suture extends to the epicondyle, or dorsal 
condyle of the mandible, and this is also true of many of the adult 
Neuroptera here figured, although in the latter insects, only the anterior 
portions of the frontal suture are retained, for the most part. A pair 
of frontal pits (“fp” of Figs. 63, 70, 42, etc.) or external manifestations 
of the internal invaginations of the body-wall forming the antero- 
dorsal arms of the tentorium, occur on or near the frontal suture in 
many Neuroptera, etc. 
As was mentioned before, the frontal suture may secondarily send 
down branches into the clypeal region (marking off the lateral areas 
labeled ‘‘pcl’’ in Figs 41 and 42), while the median portion of the 
postclypeal region ‘‘pe”’ unites with the frons “fr’’ to form a compound 
