Black wasp, pale yellow stripes across abdomen, visiting flowers of Veronica anagallis-aquatica and Solidago gigantea. Ruderal floodplain community with Kochia scoparia, Chenopodium simplex, Chenopodium berlandieri, Helianthus annuus, and Cleome serrulata. Mid-afternoon, sunny, 81 F to 85 F, light breeze. Very smoky afternoon with unhealthy air quality.

Elevation ca 4000 feet. Disturbed riparian corridor on stream restoration site within a patchwork of native and non-native grassland.

3 submarginal cells in FW, 1 apical spine on mesotibia, middle of clypeus projecting upwards, and what appears to be constriction between the first two abdominal segments tentatively point me towards Philanthinae. Seems to resemble photos of Cerceris or Eucerceris...