24 
Psyche 
[February 
The anatomy of the body in general in the Plecoptera in- 
dicates that they are among the most important of the living 
forms which have departed but little from the condition typical, 
in many respects, of the ancestors of the Orthoptera-like insects, 
and the higher orders. The venation of the fore wings of recent 
Plecoptera, however, does not furnish a particularly favorable 
basis of ’comparison in attempting to determine the paths of 
development followed in the evolution of the higher orders of 
insects, while the venation of the Protorthoptera in par- 
ticular, and in some respects that of the Protoblattids, 
(Propalaeoptera) Hadentomoids, (Proplatyptera) Megasecoptera 
etc., as well, apparently furnish certain servicable clews for 
tracing the origin of some of the developmental (evolutionary) 
tendencies exhibited in the wing venation of certain of the higher 
orders of insects. 
Since the Protorthoptera appear to be as important as any 
of the fossil forms suggestive of the precursors of the higher 
insects, it is of some interest to establish as closely as possible 
the types ancestral to the Protorthoptera. Handlirsch appar- 
ently derives the Protorthoptera directly from the Palseodic- 
tyoptera (or from the Synarmogoidea, which he derived from 
the Palseodictyoptera) ; but a comparison of the wings of 
such a Protorthopteron as Spaniodera ambulans, or even 
the Protorthopteron shown in Fig. 30, with the Protoblattid 
shown in Fig. 32, would indicate that the Protoblattids are in- 
termediate between the Protorthoptera and the Palaeodicty- 
optera. In the forewings of the lower Protorthoptera and in 
certain Protoblattids, the anal veins are numerous, and in the 
hind wings of certain Protorthoptera there occurs an anal fan 
very suggestive of that found in many Protoblattids. The 
character of the cubital vein with its numerous oblique branches 
(cubital bars) and its rather wide extent in the posterior portion 
of the fore wing, is strikingly similar in both Protorthoptera 
and Protoblattids, and the nature and extent of the subcostal 
bars, or veinlets extending from the subcostal vein to the anterior 
margin of the wing, are much alike in both groups of insects 
(Protorthoptera and Protoblattids). When the more primitive 
