This work was done in five categories as follows: 1. Documentation of development of parasitic structures of the facultative mycoparasite Parasitella parasitica on different hosts. 2. Extraction of sexual hormones in single cultures and in combined cultures of (+) and (-) mating types of zygomycetes as well as in interspecific crossing of the parasite and different hosts. 3. Spectrophotometric analysis of sexual hormones. 4. Thin layer chromatographic analysis of sexual hormones. 3. Bioassay of activity of sexual hormones using Mucor mucedo as a tester strain.