72 Annals Entomological Society of America  [Vol. XIV, 
The term vertex has also been applied to the parietals, and while this 
term is quite suitable for the parietal region of the Orthopteroid insects, 
in which the parietal region occupies the upper portion of the head, 
in other insects, such as the lepidopterous larva shown in Fig. 79, in 
which the parietals extend far forward, the term vertex is wholly 
inapplicable for the region in question, and in order to have a suitable 
term for this region in all insects, and since the sclerites composing 
this region are paired, it is preferable to refer to the sclerites between 
the frons and occiput as the parietals, as is done in vertebrate 
morphology. 
The stem of the Y-shaped epicranial suture ‘“cs’’ and “fs’’ forms 
the midcranial or coronal suture ‘‘cs’’ dividing the parietal area into 
symmetrical parts, and it is usually along this suture that the integument 
of the insect splits at the time of molting. The coronal suture ‘“‘cs”’ is 
likewise an anterior continuation of the middorsal suture along the 
median region of the back, along which the integument of the body in 
general is split at the time of molting, thus suggesting a Lamarkian 
explanation of the origin of the suture in question. Comstock and 
Kochi, 1902, state that the middorsal suture ‘‘represents the line of 
closure of the embryo.’’ While this suture may coincide with the line 
of closure of the embryo, I am inclined to consider that the middorsal 
suture (and its continuation into the head region as the coronal suture 
‘““cs’’) in some cases owes its origin to an infolding of the integument 
for muscle attachment. In the head region there is frequently a median 
dorsal ‘‘implex’’ or endoplica formed by an infolding of the integument 
for muscle attachment, and the lips of such an infolding of the body 
wall form an external suture. 
In certain lepidopterous larvee, as in the one shown in Fig. 79, an 
infolding of the integument occurs on either side of the frontal region 
“fr,” and the frontal sutures, formed by the lips of these infoldings or 
endoplice, together with the adfrontal sutures mark off an adfrontal 
area (the adfrontals “‘af’’) on either side of the frons. In the beetle 
larva shown in Fig. 38, there are also marked off on either side of the 
region labeled ‘‘fr’’ (which represents a posterior portion of the frons) 
areas resembling the adfrontals “‘af’’ of the Lepidoptera (Fig. 79); 
the sclerites labeled “‘af’’ in Figs 38 and 79, and although the regions 
are not precisely the same in both insects, may be referred to as the ~ 
adfrontals, for the sake of convenience. 
On either side of the frons ‘‘fr’’ of various Neuroptera (e. g., Figs. 
45, 56, 70, 74, etc.) there occurs a parafrontal region or parafrons, “‘pf,”’ 
usually situated between the frontal suture (or the frontal pits “fp’’) 
and the compound eyes. The parafrontals are therefore somewhat 
different from the adfrontals described above, and have been designated 
by another term, to indicate this fact. 
As was pointed out in a paper on the head region of lower insects 
(Crampton, 1917) a “ paracephalic”’ or laterocephal suture marks off a 
laterocephalic area on each side of the head capsule, in some of the 
lower forms, though these areas may possibly represent secondarily 
