1974] 
Kukalova-Peck — P ter alia 
423 
1963). In comparison with the average size of Palaeodictyoptera, 
they are much smaller and they developed the ability to flex the wings 
backwards over the abdomen. The axillary plate of the wing base 
and the basal fold were recently described by Kukalova-Peck (1974) 
in Permodiapha carpenteri of the family Elmoidae (fig. 8A). Here, 
the axillary plate is compared with that of the related family Marty- 
noviidae as preserved in Martynovia protohymenoides (specimen 
No. 4600, Museum of Comparative Zoology, Harvard University) 
from the Lower Permian of Kansas (fig. 8B). 
In both forms, the general patterns of the wing base structure are 
similar. The larger part of the axillary plate in Martynovia is 
formed by the fused medio-cubital plate, or perhaps by the cubital 
plate itself. Different is the development of the anal plate, which is 
distinctly outlined and two-lobed, located anteriorly to the basal fold. 
The anal plate is firmly connected by the anterior margin with the 
axillary plate. The basal fold encircles the axillary plate anteriorly 
and distally and separates it from the sclerotized region, extending 
between CuP and the posterior wing margin (fig. 8B, S). The 
axillary plate in both Martynovia and Permodiapha is obliquely 
crossed by a convex strut, which perhaps participated in the folding 
of the wings. The incompletely preserved axillary sclerite contacts 
,-C 
Fig. 7. Fore wing base of Permian mayfly, Protereisma permianum 
(Protereismatidae). After Carpenter, 1933. Lower Permian, Kansas. 
