New species of Phyllophaga (s.str.) are described from 12 Costa Rican localities as follows: P. tilarana new species, P. tapantina new species, P. talamancana new species, P. guapiloides new species, and P. puntarenosa new species from Cartago y Puntarenas provinces; P. naranjina new species, and P. lorencita new species from Alajuela and Cartago provinces. Most of these species are from submontane rain forests located between 800 and 1,750 m of altitude; P. talamancana and P.naranjina were collected in grasslands or coffee plantations, and P. puntarenosa was collected between 50 and 1,200 m of altitude in areas including tropical deciduous forests. Drawings of male genital capsules, female genital plates and tarsal claws are provided.