Abstract
Inbred mice of strains CBA/T6T6, A, C57BL/10Sn and B10.LP were found to be infested in ascending order of severity by Myocoptes musculinus or Myobia musculi mites. All of the 4 insecticidal preparations applied to 5-month-old mice killed the adult stages of Myocoptes musculinus within 2-6 hours, but only 1 was active against Myobia musculi. This latter was 100% active in vitro at 0.5%, but 1% was required in vivo. At 3% it killed 2 of 20 mice, but at 1% it did not interfere with insemination and reproduction, neither did it damage newborn young.