74 Annals Entomological Society of America  [Vol. XIV, 
of two occipitals “‘ocp’’ separated by a deep incision. The mem- 
branous area occupying the region between a similar incision in the 
posterior region of the head of the caterpillar shown in Fig. 79, and 
the anterior edge of the pronotum, is called the vertical triangle by 
Fracker, 1915, 
In the postero-lateral region of the head, there frequently occurs a 
narrow area called the trophifer (Crampton, 1917) since the mouthparts 
articulate with this region in the lower insects. The mawillifer (or 
“maxillary pleurite’’ of Comstock and Kochi, 1902) enters into the com- 
position of this region, and Riley, 1904, states that a portion of the 
postgena together with the “maxillary pleurite’’ arises from the 
maxillary segment, while the remainder of the postgena and the sclerites 
at the base of the mandibles arise from the mandibular segment cf the 
head. It is very strange that if the basimandibule ‘‘bmd”’ of Fig. 39 
belong to the mandibular segment, the gene immediately above them 
do not belong to this same mandibular segment (Riley attributes the 
gene to the protocerebral or first primitive segment of the head) and I 
am not entirely convinced of the correctness of Riley’s conclusions in 
this matter, especially since he wrongly ascribes the cervical sclerites 
to the labialsegment. Riley does not state to which embryonic segment 
the occiput belongs; but since the occiput occupies a considerable portion 
of the hinder region of the head, it is quite probable that it is derived 
from both the maxillary and labial segments. 
According to Comstock and Kochi, 1902, the occiput is continued 
ventrally in the postgene, but in certain insects having a well defined 
occipital region (as in the neuropterous larve shown in Figs 14 and 15) 
the occiput extends ventrally to the gular region ‘“‘gu.’’ In the beetle 
shown in Fig. 17, it would appear that the occiput “‘ocp’’ is secondarily 
marked off by the rubbing of the prothoracic parts into which the 
hinder portion of the head is received in these insects. 
The mandible articulates ventrally (by means of the hypocondyle, or 
ventral condyle labeled “‘hc’’ in Fig. 14, etc.) with a region called 
the hypostoma,* labeled “‘hs’’ in all Figures. The hypostoma ‘‘hs’’ 
is an antero-ventral region of the head (a portion of the region called 
postgena by Comstock and Kochi, 1902) situated on either side of, or 
near, the submentum ‘‘sm”’ (Figs. 15, 17, 18, 9, etc.), and is frequently 
demarked by a hypostomal ridge (or suture). Its chief distinguishing 
feature, however, is the fact that it bears the area with which the 
ventral condyle of the mandible articulates. In many insects it also 
bears a “‘fossa”’ in which the condyle of the maxilla articulates. 
The paragula is a region on either side of the gula, labeled “‘pgu”’ in 
all Figures, and is demarked laterally by the paragular ridge or suture. 
The paragular area is indicated by the shaded area “‘pgu”’ (in Figs. 
31, 13, 6, 7, 10, etc.) and forms the postero-ventral region of the head 
on either side of the gula ‘‘gu.’’ The paragula and hypostoma together 
* This region in larval Cleridz is discussed by Boving and Champlain in the 
Proceedings of the U. S. Nat. Museum, Vol. 57, p. 575, 1920, in which a discussion 
of the mouthparts of Coleoptera in general are also given. The term paragula is. 
also employed in this paper. 
