Sweltsa onkos

Sweltsa onkos (Ricker, 1936) Notes Sweltsa onkos is commonly known as the Ontario Sallfly (Stark et al. 2012). The distribution of this species extends from across southeastern Canada south to North Carolina (Surdick 2004, Kondratieff and Kirchner 2009, DeWalt et al. 2024). Museum specimens and both published and unpublished reports of S. onkos from unglaciated sections of several USA states (e. g., Alabama, Kentucky, and Tennessee) likely refer to S. hoffmani. Sweltsa onkos is one of the most abundant species in New York. Previous life history studies of S. onkos have indicated a slow two-year life cycle with most growth occurring in the second year (Harper 1973 b, Harper et al. 1991 b). Harper and Pilon (1970) reported the emergence of this species from late May to early July in Quebec. Adults have been collected in New York from mid-May through early August (Fig. 26) from a wide range of elevations from 104-1623 m asl (Fig. 27) and numerous locations across the state (Fig. 30 c).