184 
Psyche 
[June 
Figures 4 and 5. Protorthoptera. Figure 4. Hapaloptera gracilis Hand- 
lirsch. Drawing of holotype, no. 38731, U.S.N.M. (original) Figure 5. 
Heterologies langfordorum Carpenter. Drawing of holotype, Illinois State 
Museum (original). Upper Carboniferous, Illinois. 
something was amiss with the venation for he represents one vein by 
a dotted line, which crosses over the basal part of another vein. With 
the use of ammonium chloride the actual venation of the upper wing 
becomes distinct and the pattern turns out to be very close to that of 
Heterologus , from the Upper Carboniferous of the Francis Creek 
Shales (Mazon Creek), Illinois (See figure 5). In Hapaloptera gra- 
cilis , as in Heterologus , the stem of CuA (which is strongly convex) 
is anastomosed with MP, but diverges away at about the level of 
the origin of Rs and then anastomoses with the concave CuP, only 
to separate again a short distance further. The main feature which 
distinguishes Plapaloptera from Heterologus and other Cacurgidae is 
the late forking of CuP and the absence of a long basal branch on 
CuP 1. My first thought on examining the fossil was that the wing 
membrane was extensively wrinkled but further study indicated that 
the wrinkles are in most cases actual cross veins between the veins. 
Although only a few cross veins are shown in Handlirsch’s figure, they 
are almost uniformly distributed over the wing. 
