Aedes aegypti mosquito female emerging as an adult from its nymph stage at the water's surface. The emergence lasts a few minutes. The nymph stands still at the surface of the water and the back of the thorax splits and opens. The adult swells with air and slowly emerges. First the chest, then the head and the abdomen. The legs, the antennae and the trunk unfold and the wings swell out from their initial small state. A. aegypti is found throughout tropical Africa and in parts of South America. It is a vector for the transmission of yellow fever, chikungunya, dengue fever and zika viruses to humans.