It’s almost a blanket statement for all Park streams, but it is true: now is the time to fish terrestrial patterns. Be sure to have you favorite ant, beetle, and hopper patterns along. If you want action, especially on still waters, Beula Lake is the place. Gulpers (Yellowstone cutthroats, in this case) are going strong, and caddisflies coming down the inlet bring fish into shallow waters there in a mode similar to how PMD activity attracts fish to South Fork riffles. Trico activity is going on in many Park waters, so morning visits should include patterns for these. Then as mid day approaches, switch to those terrestrial patterns.