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ABSTRACT. i Eggs of aedine tr,osquitoes vary in size, outline, color, and chorionic detail according to genus, subgenus, group and evm species in most instances. Whole eggs show sufFcient specific details to permit rapid separation to species when examined in intense reflected light. Surface detaik of the chorion show patterns that are readily recogniz&le when examined as cleared material in suitable trctnsmitted light. 7axonomists will find additional support for phylogenetic concepts of the Culicidae. Sanitarians and ecologists will be able to apply the information[to extension of procedures for surveying populations of floodwater Tosquitoes. Interest in Nearctic aedine mosquitoes is increasing l&cause of their annoyance to humans and because of their ability to serve as vectors and reservoirs of agents causing disease. Unfortunately, little is known about these mosquitoes because most of them are d&cult to colonize in the laboratory. Incomplete knowledge concerning the egg stage has hampered investigation. Satisfactory methods for finding eggs in natural sites have become known only recently. Means for recognizing eggs have been unknown until recently. Lastly the sequence of events essential for hatching the eggs is at best only partially under