An analysis is given of the relationships between the genera of the tribe Cylindroiulini. The situation at present is reviewed first. Various characters are described which are subsequently used in the construction of a cladogram. The result is the splitting of the genus Allajulus Koch into three genera, Allajulus, Cylindroiulus Verhoeff, and Kryphioiulus gen. n., this last genus being erected for occultus C. L. Koch. Use of a computer program, PAUP (phylogenetic analysis using parsimony), in general confirms these divisions. The nominal genera Micromastigoiulus Verhoeff, Dendroiulus Verhoeff, Solaenoiulus Schubart, Olisteroiulus Lohmander are synonymized with Cylindroiulus. The position of the Cylindroiulini within the family Julidae is also discussed and a preliminary phylogeny presented. A key to the genera and species of the tribe Cylindroiulini, omitting species in the genus Cylindroiulus, is given in an appendix.