A new species and four new records of Diduga Moore (Lepidoptera, Erebidae, Arctiinae) from Thailand.

One new species, Diduga sphaeracephalus n. sp., is described from Thailand along with four newly recorded species, D. alternota Bucsek, 2014, D. bispinosa Bayarsaikhan Bae, 2018, D. dubatolovi Bayarsaikhan Bae, 2018 and D. allodubatolovi Bayarsaikhan, Li Bae, 2020. Illustrations of adults and genitalia of examined species are provided.