52 
Psyche 
[Vol. 90 
represent a monophyletic offshoot of the Insecta that left no 
descendants."^ 
Other possible relationships, however, may be construed on the 
basis of venational characters, particularly the nature of M in the 
fore wing. This vein is distinctive in that it either anastomoses with 
RS for a short distance, or is connected to it by a cross vein. Because 
a similar trend is seen in other groups of Protorthoptera, it may 
suggest common descent. Families, aside from the Geraridae, 
known to possess this anastomosis between M and RS are the 
Streptocladidae, Oedischiidae, Nugioneuridae, and Tococladidae. 
While many of these families (particularly the Streptocladidae) have 
a much more complex venation than the Geraridae, it may be that 
they represent an earlier stage in the evolution of the group — one 
that led eventually to the saltatorial forms represented by the oedi- 
schiids. Because the oedischiids were clearly saltatorial as far back 
as the Carboniferous, it is reasonable to speculate that the gerarids 
fall into a proto-saltatorial complex of Upper Carboniferous Pro- 
torthoptera and may represent a line of evolution quite distinct from 
that of the cursorial orthopteroids living today. 
Summary 
The family Geraridae, previously thought restricted to North 
America, and known only from Mazon Creek, was apparently a 
widespread and fairly successful group in the Upper Carboniferous. 
Careful examination of Commentry Protorthoptera has resulted in 
the synonymy of Sthenaropoda with Gerarus from Mazon Creek 
and illuminates the problems inherent in the classifications pro- 
posed by several recent authors. Recognition of the family Sthena- 
ropodidae as the sole family of the order Protorthoptera and the 
Geraridae as members of the order Paraplecoptera or Gerarida is no 
longer tenable. 
While further study is required to determine whether the Gerari- 
dae are more closely related to the Mazon Creek families considered 
"’Rasnitsyn is not the first to propose that the elongate prothorax is a 
synapomorphic character. Others, especially Handlirsch, have already suggested that 
the Geraridae are close relatives of the Spanioderidae on this basis. An argument 
against this relationship, however, is the fact that they have distinctly different 
patterns of venation. (In the Spanioderidae CUA is multiply branched and R 
branches only once. Neither character is true for the Geraridae.) 
