Contrary to popular belief, mosquitoes do not breed in tall grass or thick brush. These areas provide an excellent refuge for adult mosquitoes during the heat of the day but in no way contribute to mosquito breeding, nor do they provide habitat for mosquito larvae. Mosquito eggs are usually elongated, about one millimeter long and they lay them in batches of 50-300. One female may lay several batches. A blood meal provides the proteins necessary for egg development.
Eggs can hatch in one to three days if laid on warm water.
Other species lay eggs in containers or on the soil that may flood and require a longer drying period before hatching. Eggs of these floodwater mosquitoes have evolved to have incremental hatching, that is, all eggs do not hatch together. Many species lay eggs that remain dormant in the soil for years before hatching. The larva lives in water but breathes air through a siphon that penetrates the water surface, or, in some species pierces the roots of aquatic plants such as cattails. During the larval stage four separate developmental periods occur called instars.