1883.] On the Genealogy of the Insects. 933 
body, the head with its V-shaped suture, and the abdomen with 
its forceps, so like that of Japyx. The genus Lepisma is a rather 
more specialized form than Campodea, and Machilis is still more 
So, as proved by its mouth-parts and the presence of compound 
eyes. Scolopendrella, with its abdominal true legs, comes nearer 
to our hypothetical form than even Campodea. The group of 
Poduridze (Collembola) is most probably a series of degradational 
forms, criginally sprung from a higher, more generalized, Cam- 
podea-like ancestor. 
Il. Dermatoptera—This order, represented by but one family, 
differs, as already stated, from the Orthoptera, with which it is 
usually classified, much more than the Termitide. It stands 
alone, and, as observed, its larvæ closely resemble the Thysanu- 
ran Japyx. 
© IIL. Orthoptera—After the elimination of the Forficulide from 
the Orthoptera, we have a natural and easily circumscribed group. 
Beginning with decidedly the most generalized and at the same 
time lowest family, the Blattarize, followed by the Mantidæ, which 
have a number of characters which recall the Blattaria, we pass 
up through the Phasmidæ to the typical family, the Acrydii; 
then succeed the Locustaria, and finally the Gryllidæ, 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 Orthoptera from the 
Cinurous Thysanura. 
IV. Pseudoneuroptera—This is the most heterogeneous order 
or assemblage of Phylopterous insects. While it is comparatively 
easy to circumscribe the Neuroptera (taken in Erichson’s sense) 
and the Orthoptera, as here restricted, the group Pseudoneurop- 
tera is remarkably heterogeneous and elastic.. We have failed to 
satisfactorily diagnose the order as a whole. The Termitidæ con- 
nect the Orthoptera and Pseudoneuroptera so ‘closely that, except- 
ing in the wings and other peripheral characters, they seem but.a 
family removed from the Blattarie. For example, the Termitide 
resemble the Blattariz in the form of the epicranium, in the 
clypeus, which is but partially differentiated at the base from the 
€picranium, in the form of the labrum, and the small eyes as well 
as the mouth-parts. 
In the thorax the Termitide approach the Blattariz in the un- 
- TEA scuta of the meso and metathorax; while the pleu- 
