Blabericola rhyparobiae n. comb. (Apicomplexa: Eugregarinida: Blabericolidae) is redescribed from the Madeira cockroach, Rhyparobia maderae (Dictyoptera: Blaberidae: Oxyhaloinae: Nauphoetini). Oocysts within the genus are typically dolioform with nonprojecting polar plates. Those of B. rhyparobiae differ from all other species of Blabericola in being oblong rather than dolioform. Morphometrically, the oocysts of B. rhyparobiae are significantly narrower than those of any other known species in the genus; they are significantly longer than those of Blabericola haasi, Blabericola migrator, and Blabericola princisi, but they are significantly shorter than those of Blabericola cubensis (oocyst width 4.47 μm vs. 4.74 μm, 4.70 μm, 5.06 μm, 5.21 μm, respectively; oocyst length 8.98 μm vs. 7.94 μm, 7.93 μm, 8.85 μm, 9.26 μm, respectively). All 5 species are also distinguished by unique sporozoite-bearing cavity sizes and morphometric ratios. Gametocysts of Blabericola species are either orbicular (B. cubensis, B. princisi) or elliptoid (B. haasi, B. migrator, B. rhyparobiae). Among Blabericola species with elliptoid gametocysts, the gametocysts of B. rhyparobiae are intermediate in size relative to the much larger gametocysts of B. migrator and the much smaller gametocysts of B. haasi (gametocyst length 462.06 μm vs. 728.11 μm, 272.02 μm; gametocyst width 297.12 μm vs. 461.31 μm, 178.36 μm, respectively). No structurally unique feature of the gamont distinguishes among species of Blabericola, but gamonts of all 5 species differ morphometrically. Gamonts of B. rhyparobiae differ significantly from all other species in the genus in the primite's protomerite and deutomerite lengths, the satellite' deutomerite lengths, and the total length of both primite and satellite in association. The gamonts of B. rhyparobiae are significantly smaller than those of B. cubensis, B. migrator, and B. princisi but significantly larger than those of B. haasi and can be readily distinguished based on size alone (primite total length 460 μm vs. 563 μm, 800 μm, 547 μm, 316 μm, respectively; satellite total length 419 μm vs. 507 μm, 695 μm, 526 μm, 298 μm, respectively).