Scaeva pyrastri (Linnaeus)
Laska et al. (2006) were the last authors to study in deep the taxonomy of this genus. They concluded to divide Scaeva into two subgenera, Semiscaeva and Scaeva, based on morphological characters of the immature stages. One group (S. dignota, S. selenitica, S. mecogramma) has a distinct angle of about 90° between orificia II and III, as is typical for other related genera of Syrphini. A second group (S. pyrastri, S. albomaculata, S. latimaculata) has the orificia II and III (on spiracular plate) parallel, with insertion of orificium III beneath the level of insertion of orificium II (probably apomorphic situation).
Due to the impossibility to assign any different species with unknown larva to either group, I do not find the subgenera helpful for the taxonomy of the genus Scaeva, and at this moment both groups can be referred as species groups.
Synonyms:
Musca pyrastri Linnaeus, 1758: 594.
Scaeva affinis Say, 1823: 93.
Scaeva unicolor Curtis, 1834: 509.
Musca mellina Harris, 1780: 30.
Musca rosae De Geer, 1776: 108.
Syrphus flavoscutellatus Girschner, 1884: 197.
Scaeva corrusca Gravenhorst, 1807: 375.