Failure to Isolate Microorganisms from within Mosquito Eggs1

By means of standard bacteriological methods, attempts were made to isolate microorganisms from eggs of the following species of mosquitoes: Culex tarsalis Coquillett, Culex quinquefasciatus Say, Anopheles albimanus Wiedemann, Aedes sierrensis (Ludlow), and Aedes aegypti (L.). No microorganisms were recovered from eggs that were sterilized under the dissecting microscrope to insure complete surface contact with the sterilizing agent. Contamination in some experiments with large numbers of eggs was attributed to incomplete surface sterilization and/or to possible invasion of bacteria through damaged egg shell of some of the eggs. Larvae emerged from the uncontaminated eggs continued to live in the sterile medium for many clays.