Descriptions and measurements of life cycle stages of Geomylichus geomydis n. sp. are given. Infestation rates for G. geomydis n. sp. were determined for seasons of the year and sexes and ages of the host. A least-squares analysis of variance was used to analyze species populations in three variable categories: seasons of the year, sexes of the host, ages of the host. Significant differences were identified for G. geomydis n. sp. populations in total density/host, population age structure/host and adult sex structure/host. Scanning electron microscope photographs for G. geomydis n. sp. are included.