Figure 2. Taxonomic characters to distinguish P. nearctica from P. americana. Head of Plecia nearctica male (A) and female (B), head of P. americana, male (C) and female (D): ocelli (o), antenna (a), oral margin- forward (om-f), and oral margin- convex (om-c). Wing of P. nearctica (E): costa (c), radial sector (rs), medial cell (mc), anal cell (a), and basal cells (bc).
Credit: Buschman 1976