The genus Tectimyces gen. nov. (Harpellales: Legeriomycetaceae) is described with two species, T. leptophlebiidarum and T. robustus spp. nov., collected on the hindgut of the mayfly nymph Habroleptoides confusa (Ephemeroptera: Leptophlebiidae) in northern Spain. This is the second report of a trichomycete inhabiting a member of this family of ephemerids. Diagnostic for the new genus are type II zygospores and unappendaged trichospores, borne on long generative cells and carrying a very short collar after release. The position and morphological traits of the newly described taxa are discussed and compared with other genera and species, such as Bojamyces repens and Orphella spp.