The larva of Loberus impressus LeConte is described based on adult-associated and reared specimens collected from corollas and seed pods of Iris hexagona on the gulf coast of Louisiana. The larva of L. impressus is similar to larvae of Zavaljus brunneus (Gyllenhal) Hapalips prolixus Sharp, Pharaxonotha spp., and Bolerus angulosus (Arrow), the other described larvae within the Xenoscelinae. Larval characters typical for the Loberini that are found in L. impressus include arrangement of integumental granules into rows, frayed and aciculate setae borne on spiny tubercles, and urogomphi spiny or tuberculate and recurved. The tarsungular setae of L. impressus and B. angulosus are single, in contrast to the dual setae present in other described larvae of Languriidae. Larva and adults of L. impressus were common in dried corollas and seed pods of I. hexagona that had begun to split open or had been invaded by Crematogaster ants. Fusarium and Cladosporium fungi were potential sources of food for L. impressus and other fungivorous beetles in the iris seed pods and on corollas.