The holotype of Phylobktta gaudryi (Agnus, 1903), provided from the famous deposit of Commentry (Allier, France), exhibits a pair of forewings and a hind wing in connection, well preserved. Forewings show a network of veinlets in the area between M and CuA, and evidence of a fusion of some branches of M with CuA. It is concluded that the m-cua veinlets belong to M and that a reticulated fusion between M and CuA occurs. This fusion is considered as a homologue of the “dictyopteran forewing arculus”, but as an intermediate polymorphic state between “occurrence of a single discrete arculus“ and “no arculus”. The preserved hind wing is devoid of an m-cua arculus, has a multi-branched AA vein on the remigium, and has a vannus of limited extent. The new data on P. gaudryi might allow the phylogenetic position of Pennsylvanian stem-dictyopterans with respect to crown-dictyopterans to be better assessed.