5. Lasius (Cautolasius) flavus (Fabricius 1782)

The status of the Western Palearctic members of the subgenus Cautolasius has been debated for decades although in the absence of a rigorous morphological approach. Finally, Seifert (1983) provided evidence to consider the existence of two species, L. flavus and L. myops, differing for their ecology even if in a partially overlapping distribution (Seifert, 1983; 2017; 2018). Although morphological separation of L. flavus from L. myops is relatively easy, unfortunately the distribution of these two taxa in the Mediterranean remains little known: in particular, old records of L. flavus, which was usually considered a senior synonym of L. myops, are unreliable. In addition, the only Sicilian record of L. flavus was already considered doubtful: it was a Lasius (Chthonolasius) mixtus (Nylander 1846) record by Monastero (1950), and was later referred to L. flavus by Baroni Urbani (1971). While Baroni Urbani (1971) considered this interpretation doubtful, he did not provide any reason to support this change. By the way, the only Lasius (Chthonolasius) spp. ascertained in Sicily are L. bicornis (Foerster 1850) and L. umbratus (Nylander 1846) (Schifani & Alicata, 2018) . The presence of L. myops, and not L. flavus, even at considerably high elevation, further suggests the absence of the latter from Sicily.