Isaria sp., a caprophilous fungus, has been intensively studied and found to have produced at least 4 kinds of conidiospores during the course of its development. Macroconidiospores are thick-walled, and often found in a binucleate stage; these are oval and borne in a terminal cluster on short curved conidiophores, covering almost the entire surface of the synnema. The thin-walled microcon-idiospores are of three kinds, the spherical, and the rod shaped* which are usually irregularly arranged in loose clusters, and the oidia, the free hyphal cells breaking up from hyphal tips. Both macro- and microconidiospores may multiply by mitosis— this is more frequently noted in the macroconidiospores—or by budding. Isaria (Spicaria) species are all entomogenous, parasitic on insects but the present fungus is saprophytic on caprophilous habitat. The main characteristics of the present fungus consists of its white synnema; and hyaline, one-celled ovoid spares, which cover most of the surface of the synnema. These characteristics closely resemble Isaria cretacea (Barnett, 1960), but it is parasitic on insects rather than being saprophytic on dung. This species has not been previously reported in Taiwan.