Paper presents the first description of the so far unknown sexual generation of Pterocomma tremulae (Aphididae, Aphidinae): oviparous female and alate male. It also provides detailed description of the male reproductive system. Discussion focuses on comparative analysis of male reproductive system with other aphid groups and possible importance of its structure in resolving phylogenetic interrelationships within the genus Pterocomma. A key is provided to the known males of European Pterocomma species.
Keywords: Aphid; Populus; phylogeny; reproduction; taxonomy.