All from two sites a mile apart in east central MN. I had somewhat assumed (on range) that all might be umbrata, but giving more consideration to dates, it appears more likely most are albata going by dates given in Schmidt and Sullivan (2018). Basically albata is bivoltine, flying late May through late June and again mid August through mid September; umbrata is univoltine, flying late June through early August. Based on both range and season, I strongly suspect both species are represented here.
LEFT column WS, top to bottom: male ~23 mm; female ~22.5 mm; female ~21.5 mm; female ~22 mm; male ~23.5 mm.
RIGHT column WS, top to bottom: female ~21 mm; female ~23 mm; female ~22 mm; male ~23 mm; female ~21.5 mm.
Contrary to the Clemensia info page, my males are larger than the females. Male WS average ~23.2 mm (n=3); female WS average ~22 mm (n=7).
Overall my Clemensia records (since about 1999) from east central MN span May 15 through September 15. My northern MN records (where I have less collecting exposure, especially early-season) span June 28 through August 14 (well in line with the published flight season for umbrata).