Editha magnifica(Perty 1834) is a univoltine and subsocial sand wasp that nests in aggregations on vertical earth banks. This species was studied along a dirt road in the Horto Florestal Navarro de Andrade, Rio Claro, São Paulo, Brazil. The individuals large size and the lack of size differences among the sexes are particular morphological features of this species. The reproductive period extends from January to May. Females dig the nest prior to spending around 2 weeks provisioning it. Prey species are butterflies, mainly skippers, and diurnal moths, probably hunted on flowers. During the reproductive period males patrol the nesting site flying and hovering around the earth bank. In the reproductive peak, by April, some males can become territorial residents, defending nesting females against patrolling males. Adult wasps disappear by May, but the prepupae remain dormant in their cocoons for 8 months. I hypothesize that the evolution of dormancy in this subsocial species can be related to prey availability that prevents the overlap of generations and evolution of eusociality.