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[September 
adult stage, or later as short lateral spines on the abdominal segments 
and thorax. The following is a short account of present knowledge. 
The projections on the prothorax are, in some families, long and 
filiform, but in other families rather short, pointed and spine-like. 
They were described as spines in some Megasecoptera, namely in 
Mischoptera , Aspidothorax , Corydaloides and Foriria by Brongniart 
(1885 ab, 1890, 1893), Lameere (1908, 1917), Carpenter (1951, 
1968) and others. In 1968 Carpenter and Richardson mentioned stout 
lateral spines in the nymph of Mischoptera douglassi on the meso- 
and metathorax. 
The abdominal projections are actually filiform, growing in fringe- 
like rows out of the tergites. However, all previous authors ob- 
served only the basal parts of several abdominal projections situated 
laterally, which led to incorrect interpretations. Thus Brongniart 
(1885, p. 63; 1885, p. 658; 1890, p. 1540) considered them to be 
branchio-tracheal appendages, which served for aquatic respiration in 
nymphs and which were carried over to the adults. In his general 
account on Carboniferous insects of Commentry, he gave a detailed 
figure (1893, p. 305, p. 298, fig. 50) of an enlarged “lateral lamella’’ 
with branched “tracheae” in the genus Corydaloides (Mischopte- 
ridae). His point of view was followed by Brauer (1886, p. 107), 
who classified the projections as “persistent abdominal tracheal gills”. 
Handlirsch first (1906) stated that Megasecoptera possessed “den- 
tated lamellar appendages, which were perhaps derived from tracheal 
gills”. 
The gill character of the projections was denied by Lameere ( 1908, 
p. 136; 1917, p. 28; 1917, p. 145), who compared the “lamellae” 
with the lateral expansions of the Recent mayfly Oniscigaster wake- 
field i (N. Zealand). He regarded the projections protruding out 
from “lamellae” to be backwardly directed spines. 
Martynov (1938, p. 25) characterized Megasecoptera as having 
“lateral expansions of abdominal segments with tooth-like or spine- 
like outgrowths, homologous with prothoracic spines and prothoracic 
winglets of Palaeodictyoptera, reduced and modified”. Carpenter 
(1951, P- 353 ) correctly stated that the projections were extensions 
of tergites, but also believed them to be short and spine-like in char- 
acter (Corydaloididae, 1951, p. 351). 
A significant step in the research of the character of abdominal 
projections was the paper on megasecopterous nymphs published by 
Carpenter and Richardson (1968). In this remarkably preserved 
nymph, Mischoptera douglassi , the hind margins of the abdominal 
tergites, except the last two, bear a row of seven stout “spines”. This 
