Phenology and distribution of Italian populations of Thaumastocoris peregrinus Carpintero and Dellapé (Heteroptera: Thaumastocoridae). Thaumastocoris peregrinus Carpintero & Dellapè (Heteroptera: Thaumastocoridae) was detected for the first time in Italy in September 2011, on several Eucalyptus species and hybrids. This pest, native of Australia, was the first species of the family Thaumastocoridae found in Europe. In this paper we report data on its current distribution in Italy, where the species is present in Lazio, Campania and Tuscany. Phenological studies allowed to detect the presence of eggs, preimaginal stages and peaks of the flight of the adults. No diapausing stage were detected.