Descriptions and illustrations of a new coleopteroid genus of Lethaeini are presented. The new genusTuitocoris with one species, Tuitocoris brzoskai new species, is similar to the American genus Xestocoris and to the Australian Austroxestus. Like some other coleopteroid Lethaeini, it has several modifications in the hemelytra and hind wings. Dorsal views of male, head, foreleg, mesothoracic scent gland, paramere, pygophore, spermatheca, and fifth instar nymph are illustrated. This species was found in an area of pine forest on the coast of the state of Jalisco, Mexico, which is known for the great number of endemic species of Heteroptera and some other groups of insects and plants, so it should be considered for conservation purposes.