A description and diagnosis are given for Hoplothrips cooperi sp. nov. collected from leaf litter beneath Chilopsis linearis (Cavanilles) Sweet (Bignoniaceae) shrubs in the Mojave Desert in southern Nevada. All adult males and most adult females are apterous, with macropters produced only in females. I examined the phenology of the species at a single locality during 27 November 2018 to 19 June 2019. Three generations were evident during winter and spring from the densities of larval and pupal instars. The timing and abundances of these generations appeared dependent on rainfall, consistent with thrips feeding on fungi growing on moist, dead leaves and stems. Most apterous adults and all macropterous females were collected during late spring when thrips densities and leaf-litter temperatures were highest. Hoplothrips cooperi appears to be the first species in the genus to be collected from leaf litter in the western U.S. and Mexico.