Metallic blue-green beetle on open inflorescence of Solidago gigantea. Collected. 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.

Keyed to species in Lindroth 1961. Characters pointing to Lebia included the truncate elytra; inner metatibial spine less than half as long as the first tarsomere; apical tergite with a medial keel; and the elytral suture with a plica visible subapically. The completely dark, iridescent elytra and pronotum, plus completely dark antennae, greatly narrows the possibilities to a few species, of which L. moesta, which averages smaller (but overlaps in size), with narrower pronotum and less prominent eyes, is the most similar. Basal ridge of the elytra reaching the scutellar stria, or almost so.

According to Lindroth, larvae of this species are thought to parasitize pupae of Altica sp. chrysomelids, whose coloration they resemble. I have observed Altica sp. feeding on Alnus incana on this site in previous years, so I will be looking for these two beetles associating in the future.