426 Psyche [September-December 
— anal plate; Axe — convex axillary sclerite; Axe — elongated axillary 
sclerite; np — narrow plate; ScPl — subcostal plate. Lower Permian, 
Kansas. 
major difference in the pteralia, not only with respect to Palaeodicty- 
optera, but also to all other paleopterous orders. 
The well preserved wing bases with axillary sclerites were found 
in specimens of two comparatively small species: Protohymen permi- 
anus (specimen No. 3060) and Protohymen readi (holotype No. 
3258), in the Museum of Comparative Zoology. Since the structures 
in both specimens are similar, only the wing bases of Protohymen 
permtanus, which is better preserved, are described (fig. 10). 
