Diopsosoma Malloch, 1932 and its only included species, D. primum Malloch, 1932 are redescribed. While the genus is remarkable and easily recognized by its laterally elongate head that is produced into eyestalks, it is otherwise virtually unknown. To bring attention to this extraordinary fly we redescribe it within the context of brief descriptions of the family Periscelididae and subfamily Periscelidinae. We also provide an annotated key to the described genera of Periscelididae and a photographic montage of the holotype, which is perhaps the only preserved specimen of this genus and species.
Diopsosoma primum; Diptera; neotropics; Periscelididae
