Probing mosquitoes salivate before ingesting blood, and malaria sporozoites are transmitted during this phase of feeding. Large and small Aedes aegypti infected with Plasmodium gallinaceum were allowed to probe briefly on a series of 3 naive chicks. Large mosquitoes were more infective overall, but there was no difference in the ability of either size class to infect the first host. Large mosquitoes were more likely than small mosquitoes to infect more than one host during serial feeding.