Twenty-two new species of the genus Eviulisoma Silvestri, 1910, from the Eastern Arc Mountains, Tanzania, are described: E. acaciae sp. nov., E. aequilobatum sp. nov., E. akkariae sp. nov., E. angulatum sp. nov., E. articulatum sp. nov., E. biquintum sp. nov., E. breviscutum sp. nov., E. cetafi sp. nov., E. chitense sp. nov., E. commelina sp. nov., E. coxale sp. nov., E. ejti sp. nov., E. grumslingslak sp. nov., E. kalimbasiense sp. nov., E. navuncus sp. nov., E. nessiteras sp. nov., E. ottokrausi sp. nov., E. paradisiacum sp. nov., E. sternale sp. nov. and E. zebra sp. nov. from the Udzungwa Mts, E. culter sp. nov. from the Rubeho Mts and E. kangense sp. nov. from the Kanga Mts. Eviulisoma kwabuniense Kraus, 1958, and E. dabagaense Kraus, 1958, both from the Udzungwa Mts, are redesribed based on new material. Notes are provided on E. iuloideum (Verhoeff, 1941) based on type material. Eoseviulisoma Brolemann, 1920, is synonymized under Eviulisoma, based on newly collected material of E. julinum (Attems, 1909), type species of Eoseviulisoma. New material of Suohelisoma ulugurense Hoffman, 1964, type species of Suohelisoma Hoffman, 1964, has revealed that the gonopod structure is more similar to that of Eviulisoma than originally thought, but Suohelisoma is retained as a valid genus. Four species groups are recognized among Eviulisoma species from the Udzungwa Mts, but the need for a revision of the entire genus is emphasized. Two types of epizootic fungi are recorded from Eviulisoma spp., and an enigmatic amorphous mass, which may be a kind of plugging substance, is recorded from the gonopod tips and excavated sixth sternum of several species.