272 Notes on the derivation of winged insects throngh several lines etc. 
is diffieult to conceive of any other way of interpreting this fact than 
on the assumption that they are the descendents of a common ancestor, 
It is preferable to regard the Japix-like forms as the common ancestors 
of both Coleoptera and Dermaptera, rather than to attempt to derive 
the Coleoptera from the Japyx-like forms through the Dermaptera, despite 
the fact that the earwigs are in many respects much more primitively 
organized than the Coleoptera. 
The Myriento-Platyptera line, leadiug from the Myrientomata to 
the Platyptera (i.e. the Plecoptera and Embioidea) is a much more 
primitive one, or branched off from the common stock much lower 
than the Dicelluro-Dermaptera line, and includes forms which are, 
structurally speaking, among the most primitive of the apterygote and 
pterygote insects. In some respects, the Plecoptera are more closely 
related to the Myrientomata (such as Eosentomon) than the Embioidea 
are, and may possibly represent a stage of development intermediate 
between the Embioidea and the Myrientomata (i. e. the lines of deve- 
lopment would be expressed as the Myriento Plecoptera and the Pleco- 
ptero-Embioidea lines). Provisionally, however, I prefer to consider 
the Myrientomata as the common ancestors of both Plecoptera and 
Embioidea, so that it is preferable to express the developmental series 
as the Myriento-Plecoptera and the Myriento-Embioidea lines of descent. 
Turning for a moment to the consideration of the higher forms, 
such as the Diptera, Mecoptera, Trichoptera, Lepidoptera and Hemi- 
ptera, a comparative study of the anatomy of these forms suggests. 
a community of descent from ancestors whose nearest living represen- 
tatives are to be found in the heterogeneous group Neuroptera.* From 
the ancestors of the Neuroptera, there have been given off several lines 
of descent. One of these is the Neuroptero-Trichoptera line, which either 
gave rise to a Trichoptero-Lepidoptera line, or is closely related to 
a Neuroptero-Lepidoptera line. Another line near these is the Neuro- 
ptero-Mecoptera line leading to the Panorpidae, and quite near those 
mentioned above, is the Neuroptero-Diptera line To these may be 
added the Neuroptero-Homoptera line, which is doubtless a composite 
one, but for the sake of brevity, it may be signated simply as the 
Neuroptero-Homoptera line, without attempting to resolve it into its 
component parts. 
Thus far, it has been comparatively „smooth sailing“, but 
when we attempt to trace the Neuroptera to'some one of the more 
primitive types, we at once encounter considerable diffieulty. One of 
the most promising lines to suggest itself, is the Platyptero-Neuroptera 
line leading from the Plecopteron branch of the Platyptera, to the 
Neuroptera (it might be more exact to refer to this line as the Pleco- 
ptero-Neuroptera line, since it leads from the Plecopteron branch, in- 
stead of froın the Platyptera as a whole). There may have been 
a Platyptero-Mantieformia line closely paralleling the latter, and leading 
from the Embioidean branch of the Platyptera to the Mantiefornia 
*) The Coniopterygoidea, Sialoidea, Hemeroboidea, Nemopteroidea, Mantis- 
poidea, Raphidoidea, Myrmeleonidea and Ascalaphoidea form a heterogeneous 
collection which should be split up into other groups. The Ascalaphoidea, for 
example, should be placed in another order, the Arcyptera (or net-winged forms), 
and the Myrmeleonidea should perhaps be included with them. 
