1971] Carpenter & Richardson — Pennsylvanian Insects 275 
about 23 mm., to the edge of the nodule, and it undoubtedly orig- 
inally extended beyond that point. Pairs of strong, flat, setiferous 
spines project dorsally and somewhat posteriorly from the abdomen, 
arising directly on the posterior margins of the tergites. The first 
spine is short; the second, third and fourth are nearly as long as the 
width between them; the fifth is short; a very slight projection 
marks the position of the sixth and there are none in the more 
posterior positions. These spines do not appear to mark the lateral 
edges of the tergites, which do not have their full widths preserved. 
The spines that are preserved in the fossil are about 3.5 mm. apart 
laterally and were almost certainly a little to each side of the median 
longitudinal axis of the abdomen. Other spines along the posterior 
tergal margins were probably present near the sides but can only be 
assumed since the lateral portions of the segments are broken away. 
In all probability the tergal spines in Notorachis were similar to those 
already described in the megasecopterous Mischoptera douglassi , 
though the strong, dorsally projecting spines just described are flat- 
tened parallel to the body axis rather than parallel to the surface of 
the tergites. (See Carpenter and Richardson, 1968, p. 306). It is 
pertinent to note that prothoracic spines were also present in Mis- 
choptera. 
Holotype: No. PE21699, Field Museum of Natural History; 
from the collection of Mr. and Mrs. Francis A. Wolff, Park Forest, 
Illinois, who collected the unique specimen in Pit Eleven. The spe- 
cies is named for both Mr. and Mrs. Wolff. 
This insect is unusual, among the Palaeodictyoptera so far known, 
in having elaborately modified pronotal lobes; the only other species 
that may approach Notorachis wolff orum in this respect is Stilbocro- 
cis heeri (Goldenberg) (Upper Carboniferous of Germany), which 
is, however, a member of the Dictyoneuridae. In Stilbocrocis the 
lobes are smaller than in Notorachis and possess fewer spines. 8 
The most puzzling aspect of this fossil is the shortness of the 
pterothorax and the consequent overlapping of the fore and hind 
wings. Since this overlapping is symmetrical for both pairs of wings, 
it is almost certainly not due to distortion during preservation. Fur- 
thermore, the thorax itself is so short that the overlapping would 
8 Stilbocrocis has consistently been represented in the literature as having 
large pronotal lobes, bearing a series of radiating veins within the lobes 
themselves. From a recent examination of the type specimen (on deposit 
in the Natural History Museum at Bonn), I am convinced that the radiat- 
ing ridges are actually spines which project beyond the edges of the lobes. 
A detailed account of this fossil will be published elsewhere. (FMC). 
