We provide the first record of the leaf chafer beetle Leucothyreus suturalis Castelnau (Coleoptera: Scarabaeidae: Rutelinae) associated with nests of Cornitermes cumulans (Kollar) and Silvestritermes holmgreni (Snyder) (Termitidae: Syntermitinae), including notes on the life cycle of the guest. We found 13 third-instar larvae in eight nests of C. cumulans and eight third-instar larvae in a single nest of S. holmgreni located in pasturelands or in forest edges of the Brazilian Atlantic Forest. In nests of both termite species, L. suturalis larvae were found imbedded in peripheral areas of nests. Larval development was similar regardless of the termite host nest. We supplement the knowledge of scarab—termite associations, report the first leaf chafer (Rutelinae) association with termite hosts, and provide life history comparisons of termitophile versus nontermitophile in the genus Leucothyreus MacLeay.