Acrosathe Irwin & Lyneborg 1981

Acrosathe Irwin & Lyneborg Acrosathe is a Holarctic and Oriental genus (Webb 2009). Males usually are covered in silver-white hairs, at least on the abdomen. Many species live on coastal sand dunes but others inhabit mountains and are often found on lake beaches and other sandy habitats near water. Webb (2009) gives keys to the males and females of the North American species. Acrosathe otiosa (Coquillett) is the only species of the genus previously recorded from British Columbia and Canada (Webb et al. 2013). All specimens of Acrosathe from British Columbia that we have examined key to A. vialis, based on wing colour and most male genitalic characters. This even includes some specimens identified as A. otiosa by D.W. Webb, the revisor of the genus and author of the species identification key (Webb 2009). In one case, specimens collected at the same place, on the same date, by the same collector were identified as both A. otiosa and A. vialis; males as the former, females as the latter. Acrosathe otiosa and A. vialis are very similar morphologically and distinguishing them is problematic as some of the diagnostic characters are somewhat variable. For the purposes of this study, we include A. vialis as a British Columbia species but also accept A. otiosa because of the identifications of unexamined specimens in databases and the literature. This study is not a revisionary systematic work; we expect future work on the genus will clarify this taxonomic confuseion.