296 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
fled, much more thau the Termitid®. It stands alone, and, as observed, 
its lame closely resemble the Tbysanuran Japyx. 
III. Orthoptera . — After the elimination of the Forficulid® from the 
Orthoptera, we have a natural and easily circumscribed group. Begin- 
ning with decidedly the most generalized and at the same time lowest 
family, the Blattari®, followed by the Mantid®, which have a number of 
characters which recall the Blattari®, we pass up through the Phasmid® 
to the typical family, the Acrydii; then succeed the Locustari®, and 
finally the Gryllid®, which on the whole are farthest removed from the 
stem-forms of the order, the Cockroaches. The close resemblance of a 
larval Cockroach to Lepisma indicates the direct descent of the Ortho- 
ptera from the Cinurous Thysauura. 
IV. Pseudoneuroptera . — This is the most heterogeneous order or as- 
semblage of insects. While it is comparatively easy to circumscribe 
the Neuroptera (taken in Erickson’s sense), and the Orthoptera as hero 
restricted, the group Pseudoneuroptera is remarkably heterogeneous and 
elastic. We have failed to satisfactorily diagnose the order as a whole. 
The Termitid® connect the Orthoptera and Pseudoneuroptera so closely 
that, excepting in the wings and other peripheral characters, they seem 
but a family removed from the Blattari®. For example, the Termitid® 
resemble the Blattari® in the form of the epicrauium, in the clypeus, 
which is but partially differentiated at the base from the epicranium, in 
the form of the labrum, and the small eyes as well as the mouth-parts. 
In the thorax the Termitid® approach tbe Blattari® in the undiffer- 
entiated scuta of the meso- and metathorax; while the pleurites are 
also very oblique and the femora are flattened and ovate in form, as in 
Blatta. In the abdomen, as regards the form of thetergites, as well as 
the urites and pleurites, besides the form of the end of the abdomen and 
of the cercopoda, the Termitid® closely approach the Blattari®. The 
degree of metamorphosis is also the same. 
On the other hand, the close relationship of the Termitid® to the 
Em bid®, as well as to the Psocid® and also the Perlid®, and the close 
resemblance of the Perlid larv® to those of Odouata and Ephemeriua, 
forbid our removing the Platyptera from the Pseudoneuroptera. 
We conclude, then, that the Ephemeriua, Odouata, Platyptera, as 
well as Orthoptera and Dermatoptera have had a common origin from 
some Tbysanuran stock. It is possible that these five groups are nearly 
equivalent and should take the rank of orders, but the classification we 
have given in the tabular view on p. 294 may better express their rela- 
tions. 
The Odouata and Ephemeriua are, as regards the wings and meta- 
morphosis, a good deal alike. The Ephemerina, while having a highly 
concentrated thorax, are, as regards the mouth-parts and hind wings, 
degradational forms, the result of probable degeneration from a primi- 
tive, lost form. From what group the Ephemerina may have originated 
it seems to us impossible to conjecture. 
