A new species of the genus Dicraeus was observed in numbers ovipositing on the heads of rain-fed millet in Upper Volta. In Senegal, it was reared in field trials from heads that had been exposed for one week following onset of flowering, the highest infestation being in heads that flowered during the first two weeks in October. In Nigeria, larval feeding lesions and withering were observed in seeds from individual inflorescences containing pupae. The species is described as D. pennisetivora sp. n. from the adults of both sexes, puparium and third-instar larva. A further three African species that are closely related to it are described from adult material alone, and the characters of the adult terminalia of two further closely related but already described species are given. The six species are keyed. There being no previous description of the larva of any species of this genus, the larva is likened to those of other chloropid genera. The generic diagnosis is modified. It is suggested that within this genus the structure of female terminalia determines the structure of male terminalia, in which case subgenera based upon characters of male terminalia are purely artificial.