GONZO on Aug 25, 2011August 25th, 2011, 10:17 am EDT
Might this specimen have been mislabeled? It appears to be a better match for A. subnotatus than A. oregonensis. The adult key in Zloty (1996) distinguishes A. subnotatus by the dark margins on the crossveins ("giving them a speckled appearance and forming three or four larger dark patches") and dark suffusion only at the base of the hindwing (Fig. 44B). A. oregonensis is supposed to lack the dark margins on the crossveins and have dark suffusion at the base of both the forewings and the hindwings (Fig. 44A). Table 1 in Zloty and Pritchard (1997) seems to qualify this slightly and describes oregonensis females "with brown shadings around some cross-veins but without brown patches."
McCafferty and Newell (2008) contains this record:
Ameletus subnotatus Eaton.
FLATHEAD COUNTY: Hungry Horse Creek, (A) 12-V-2005, R. Newell [FLBS]