Pomona College, Claremont, California 51 
As was stated above, the Dermaptera have many features in common with the 
Embiide and Plecoptera, and similarly, the Coleoptera (whose line of development 
appears to parallel that of the Dermaptera quite closely) have also retained certain 
features which occur in the Embiide and Plecoptera. Since the Coleopteron line of 
development parallels that of the Dermaptera quite closely, and since the Dermaptera 
have rather more in common with the Embiids than with the Plecoptera, the Coleop- 
tera also are rather more like the Embiids than they are like the Plecoptera, as might 
be expected. Bearing these facts in mind, and taking the composite features of the 
superorder Panplecoptera as a whole, for comparison with the composite characters 
of the Coleoptera as a whole (since some members of a group will retain certain 
primitive features which other members do not retain), I would point out the follow- 
ing similarities between the Coleoptera and the other members of the superorder Pan- 
plecoptera, which, to my mind, indicate that the ancestors of the Coleoptera were 
like certain insects belonging to this superorder rather than to any other 
Both the Coleoptera genuina and the Dermaptera are typically prognathous (mouth 
parts directed forward) as is true of most of the insects belonging to the superorder 
Panplecoptera. The segments of the antenne in certain Coleoptera, such as the Ceram- 
bycids, ete., are very like those of certain Dermaptera. The nature of the maxille 
with its peculiar subdivisions in these two groups is markedly similar in both Coleop- 
tera and Dermaptera. The character of the labium of the Coleopteras, on the other 
hand, is more like that of the Embiids, in which there is a tendency toward the union 
of the under lip with the head capsule and a demarking of a longitudinal gular 
region on the under surface of the head. There is a well-defined tendency toward 
a thickening of the fore wings in some Plecoptera, and in certain of them the fore 
wings become greatly shortened, and but few veins (mostly the longitudinal ones) are 
retained in some cases. In the Embiids, the tendency toward the retention of the 
longitudinal parallel venation is even more marked; but the thickening of the wings 
is not so pronounced, although traces of it are to be found even among the Embiids. 
The thickening of the fore wings to form elytra is very marked in the Dermaptera, 
in which they are extremely like the elytra of certain Coleoptera. Some of the flat- 
tened Dermaptera such as Hemimerus have broader pronota resembling the pronota of 
certain Lampyrids, while other Dermaptera have narrower pronota like those of other 
Lampyrids. The neck plates of the Coleoptera are more like those of the Embiids, 
but the prothoracic sclerites of the Coleoptera are more like those of certain Dermap- 
tera, in which the trochantinus intervenes between the bases of the coxa and the pleural 
region which tends to unite with the pronotum in both groups. The legs of the 
Coleoptera could readily be derived from the Dermaptetron type, except that the 
tarsi of the Dermaptera, like most of the other primitive members of the Panplecopteron 
group, are trimerous. The posterior coxe of the Coleoptera are more like those of 
the Embiids than those of the Dermaptera, and the general plan of the meso- and 
metathoracic sclerites (with the exception of the tergal region) is somewhat more 
alike in the Embiids and Coleoptera, although the mesonotal and metanotal regions 
of the Coleoptera and Dermaptera are astonishingly similar even to the minutest 
details, as was pointed out in a paper dealing with this subject in Vol. 25 of Psyche 
(p. 4). The abdnominal paranota (lateral projections of the tergal region) of cer- 
tain Lampyrids and other Coleoptera are also present in such Dermaptera as 4 ncistro- 
gaster luctuosus Stal. It may be remarked in passing, that the paranota are very 
ancient structures occurring in Paleodictyoptera, certain primitive Ephemerida (nymphs 
