Hydrotaea borussica Stein, 1899 Novenkovsky

Vikhrev, Nikita E., Esin, Mikhail N., Yanbulat, Maria O. & Ruchin, Alexandr B., 2020, A list of the Sciomyzidae, Fanniidae and Muscidae (Diptera) of Mordovia, Amurian Zoological Journal XII (4), pp. 444-459 : 451

12. Hydrotaea borussica Stein, 1899 Novenkovsky cordon, 54.931°N 43.421°E, 4–7 July 2020, K. Tomkovich, 3♀.

REMARKS. Vikhrev (2013) reviewed Hydrotaea irritans group. In “Notes on identification of females” he suggested that the generally accepted understanding of females of H. borussica as having dark abdomen with a pair of shining spots on tergite 3 is erroneous. According to Vikhrev (2013, 287), the presence of shining spots on tergite 3 is not a genetic character but a result of wiping of abdominal dusting by wings in aged female specimens. Without paying attention to the presence or absence of shining spots, females of H. pandelei and H. irritans have the abdomen entirely dark, while females of H. borussica have part of the abdomen yellow.

Females of H. pellucens collected in Mordovia in 2020 have the abdomen translucent yellow only at lateral sides of syntergite 1+2 (Fig. 8) as well as those collected in 2019 in Belarus. Such abdominal pattern for females of H. pellucens was also indicated by Gregor et al. (2002). However, three females from the Hydrotaea irritans group collected in early July have sides of abdomen extensively yellow (Fig. 7). We identified these females as H. borussica though some doubt remains unless male specimen(s) are collected.