Posted to verify genus & species.
Posted to extend BugGuide map range for genus & sp. into UT.

ID made With the help from both of the following.
-- iOS Adalia app by James Bailey.
AND...
Characters below are from Arnett Beetles Vol 2 (1).
Head------------
--Antennae short (2/3 of head width or less).
--Antennal segment #3 longer than remaining segments.
--Antennal club rounded, not spindle shaped.
--Antennae inserted in front of the eye.
--Maxillary palpomeres expanded distally (securiform).
--Eyes without any canthus or emargination (see several pics).
Thorax------------
--Prosternal intercoxal process with carinae.
Abdomen-----------
--Postcoxal line of abdomen reaching posterior margin, not recurved.
--Dorsal surface pubescent.

Study = GBBL MeSa. Sample 137.6.361 (Site.Plant.sp)
Collector = M.L. Forister, Ph.D, Great Basin Bug Lab.

January 2024
More experienced now and also in possession of Gordon (2) with a key to the Diomus species, this specimen keys to D. debilis.