The egg of Aedes hendersoni is described with the aid of scanning electron micrographs and its structure is compared with the egg of Ae. triseriatus. The egg of Ae. hendersoni is broadly cigar-shaped, with the dorsal surface (cemented to the substrate) distinctly more rounded in longitudinal profile than is the ventral surface. The micropylar collar is fairly conspicuous and substantially thicker on the ventral side. Ventral outer chorionic cells contain four to eight low, flat tubercles, the largest ones positioned in the cell corners. Cell structure changes transitionally down the lateral surfaces to the dorsal surface, where many small, more or less round tubercles are irregularly clustered around the periphery of each cell. Eggs of Ae. hendersoni differ significantly in several respects from those of a sympatric population of Ae. triseriatus. Aedes hendersoni eggs are wider and their length/width ratio is smaller; the cells of the ventral (upper) surface are larger in area and contain more tubercles which occupy a greater proportion of the cell field; the reticulum is narrower; the structure of the dorsal surface cells is distinctly different; the micropylar disk area takes up a smaller percentage of the area within the collar. Differences found between eggs of Ae. triseriatus from Michigan and Florida are discussed.