Like other mosquito larvas, A. aegypti has a 9-segmented abdomen. The anal segment of the abdomen has 4-lobed gills and a short air tube or siphon for breathing. Two prominent lateral spines are seen on each side of the thorax with a dissecting microscope. Resting at the water’s surface, this mosquito hangs vertically. Larvas swim smoothly like a snake. When disturbed by light or other, they will go to the bottom of the container.

The first instar feeds a day or 2, then moults to the second instar. Head parts harden and darken. After the second stage, the thorax and abdomen will grow without the head and siphon increasing size. Hatching to pupation could be 7-14 days or even less depending on conditions. The fourth instar is a long stage. Under starvation the emergence of pupas can take several weeks. Also, male larvas and pupas develop more rapidly than females.