4 
Psyche 
[Vol. 90 
only by our imagination, and having this proof provides a base on 
which insect phylogeny and early insect evolution can be recon- 
structed. 
Clearly, revisionary studies on Paleozoic insects are important. 
Fortunately, recent revisional work by Carpenter has greatly in- 
creased our knowledge of certain Paleozoic orders (i.e., the Paleodic- 
tyoptera, Megasecoptera, Diaphanopterodea, Protodonata, and 
Caloneurodea), but much work on the Protorthoptera remains. 
This revision of the family Geraridae is, at least, a beginning and is 
intended to be the first in a series of family-level studies on Upper 
Carboniferous Protorthoptera. 
Selection of the Geraridae as a starting point was influenced, 
ultimately, by two factors: 1) it is typical of many of the families in 
the Protorthoptera, having last been studied in the early part of this 
century (despite the discovery since then of new material assignable 
to the family); and 2) the Geraridae are morphologically most unus- 
ual insects. They were large (up to 75 mm in body length), and had 
as their single most distinctive attribute, a prothorax that was elon- 
gate, flask-shaped, and adorned with long, numerous spines. These 
spines gave them the appearance of walking pincushions, and pre- 
sumably provided some defense against vertebrate predators. 
The systematic importance of the family plus the impact this work 
has on current classifications of the Protorthoptera will be discussed 
in subsequent pages. The remaining sections of this paper cover (in 
the following order): the systematics of the Geraridae; paleoecologi- 
cal differences between the two localities at which gerarids have 
been found (Mazon Creek and Commentry); and the significance of 
this study relative to phylogenetic relationships within the Pro- 
torthoptera. 
Systematics 
Materials and Methods 
The fossils examined for this study occur mostly as impressions 
(imprints in a sedimentary matrix devoid of organic matter) but 
some occur as compressions (in these, organic matter is present, but 
usually coalified). Both types of fossils were prepared by degage- 
ment,^ i.e., an uncovering of the fossil by removal of the overlying 
rock matrix. This is generally done using a fine pneumatic drill and 
From the French verb degager meaning to disengage, extricate, or get clear. 
