8 Psyche [February 
region of the tergum called the suralare (Crampton, 1914-1916) 
and serves as one of the pivots for the wing in the movements of 
flight, although it may become detached from the remainder of the 
tergum in a few rare instances, as Pantel considers to be the case 
in the Dermaptera. The posterior wing process “a” of the meso- 
thorax is very similar in both Coleoptera and Dermaptera (Figs. 2 
and 4), being rather long and slender in these insects, while it is 
shorter and more blunt when it occurs in other members of the 
group (Fig. 1, “‘a’’). The basanal pterale “sa” is proportionately 
much larger in the metathorax of the Coleoptera and Dermaptera 
(Figs. 2 and 4) than in the Plecoptera and Embiids (Figs. 1 and 3). 
In both the Coleoptera and Dermaptera (Figs. 2 and 4) there is 
a pronounced tendency for the tergal region of the wing bearing 
segments to become broader than long, and, with the Strepsiptera, 
and certain Orthoptera, these insects comprise the few forms in 
which the metathorax surpasses the mesothorax in size. Unlike 
the Plecoptera and Embiids, there is a well marked tendency in 
the Coleoptera and Dermaptera (Figs. 2 and 4) for the mesonotum 
to take on a triangular outline, and for the scutellar region of the 
mesonotum to become pointed posteriorly and to overlap the an- 
terior portion of the metanotum behind it. Correlated with this 
tendency for the scutellum of the mesonotum to overlap the meta- 
notum in the Coleoptera and Dermaptera, there is a well marked 
tendency toward the reduction of the mesothoracic postscutellum, 
which is well developed in the Embiids and Plecoptera. 
In the metathorax of Coleoptera and Dermaptera (Figs. 2 and 
4) two alar ridges or “alacristae”’ labeled “ac” serve to hold the 
elytra in place when at rest, and in many Dermaptera, they are 
provided with bristles which doubtless aid in holding the elytra in 
position. In both Coleoptera and Dermaptera, the metathoracic 
scutum is traversed by a “transscutal suture” (“‘tr”’ of Figs. 2 and 
4) which is apparently absent in most of the other members of this 
superorder; and it is at once apparent from the study of the tergal 
region and the wing bases, that the Coleoptera are very similar to 
the Dermaptera in regard to these features, while the Embiids are 
very similarto the Plecoptera in the character of their tergal regions 
and wing bases. 
The presence of the posttergal fold “pt” of Fig. 4 is a “ Pandic- 
tyopterous”’ character (well developed in Isoptera, Mantids, ete.) 
