Milbemycin A3 and Milbemycin A4 (Mixture); (6R,25R)-5-O-demethyl-28-deoxy-6,28-epoxy-25-methyl-milbemycin B and (6R,25R)-5-O-demethyl-28-deoxy-6,28-epoxy-25-ethyl-milbemycin B (Mixture); Antibiotic B 41A3 and Antibiotic B 41A4 (Mixture),Milbemectin API