Four species of mosquitoes, Aedes aegypti, Ae. triseriatus, Culex pipiens and Cx. tarsalis, were allowed access to defibrinated rabbit blood via 4 different membranes and a standard membrane feeder. Natural animal skins (mouse or quail) were the most effective. More than 50% of the Aedes mosquitoes fed within 5 min and approximately 90% fed within 20 min on either mouse or quail skin. Culex species fed best on quail skin, but the difference in feeding on quail skin and sheep intestine was not significant at 10 or 20 min. In general Culex mosquitoes fed less readily on natural animal skins than Aedes.