PSYCHE 
Vol. 75 December, 1968 No. 4 
MEGASECOPTEROUS NYMPHS IN PENNSYLVANIAN 
CONCRETIONS FROM ILLINOIS 
By F. M. Carpenter, Harvard University 
AND 
Eugene S. Richardson, Jr., Field Museum of Natural History 
Recognition of immature stages of insects belonging to extinct orders 
is peculiarly difficult. We have no definite knowledge of the im- 
mature forms of any extinct order except the Protorthoptera. The 
few specimens of nymphs which have been placed in the Palaeo- 
dictyoptera almost certainly belong elsewhere; at any rate, they do 
not show features which justify their reference to that order (Car- 
penter, 1948). * 1 Possible nymphal forms of the Megasecoptera have 
been described by Handlirsch and by Bolton. Lameereites curvipennis 
Handlirsch, from the vicinity of Mazon Creek, Illinois, was based on 
a single specimen consisting of four “wing cases” (Handlirsch, 1911, 
p. 374)- The homonomous nature of the wing cases, their shape and 
venation led Handlirsch to believe that they were Megasecoptera, 
although he did not attempt a family assignment. No body structures 
were mentioned or figured but he was of the opinion that the position 
of the wing cases, “on the sides of the thorax . . . strongly spread out” 
was a primitive one. Several isolated nymphal wings from British 
Upper Carboniferous strata were described by Bolton (1921) as 
belonging to the Brodiidae, which he considered to be Palaeodicty- 
optera, though most workers have placed them in the Megasecoptera 
(see Carpenter, 1967). 
There has at last been collected, in an ironstone nodule from the 
Francis Creek Shale of Illinois, a magnificently preserved nymph 
a Since the publication of this 1948 paper, one additional Carboniferous 
nymph ( Rochdalia park^ri Woodward) has been referred to the Palaeo- 
dictyoptera (Rolfe, 1967). I have not seen this fossil, but on the basis of 
the published photographs and the conclusions reached in the present paper 
I seriously doubt the correctness of that assignment. F.M.C. 
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