The mid-Cretaceous termite genus Arceotermes Engel & Jiang (Arceotermitidae) has hitherto been known from a single species in Kachin amber (Myanmar). Here we report a second species, which is described and figured as Arceotermes bellator sp. nov., permitting an emendation of the generic diagnosis. The new species is distinguished from the type species by mandibular dentition and number of antennomeres. We discuss its systematic placement in detail, and propose of brief summary of the defensive strategy used by termite soldiers during the mid-Cretaceous.