A new genus (Xeroniscus) and three new species of terrestrial Isopoda (X. nogalensisandX. penicilligerfrom northern Somalia, andX. angusticaudafrom the People's Democratic Republic of Yemen) are described. Three species previously ascribed toPeriscyphisare transferred toXeroniscus(X. brevicaudatusfrom southern Somalia,X. erythraeusfrom Ethiopia and Saudi Arabia, andX. bicoloratusfrom the Yemen Arab Republic). The position of the new genus in the family Eubelidae is discussed.