Comments on the presumed holarctic occurrence of the horse fly Hybomitra nitidifrons (Diptera: Tabanidae)

Hybomitra nuda (McDunn.), which is common in the Nearctic Region, was recently reduced to a subspecies of the less common Palaearctic species H. nitidifrons (Szil.). Attention is drawn to several morphological characters that collectively distinguish the adults of these flies, and it is concluded that reduction of H. nuda to a subspecies of H. nitidifrons was premature without more substantive evidence, such as the comparison of the immature stages of the 2 taxa.