Egg, larva, and pupa stages of Anopheline and Culicine mosquitoes

(A) Female mosquitoes lay up to 200 cigar-shaped eggs per reproductive cycle. Both Anopheles and Aedes (a vector of several arboviruses) mosquitoes lay their eggs individually; the eggs have characteristic "floats." Culicine mosquitoes lay their eggs in groups ("rafts").

Anopheles mosquitoes prefer to lay eggs in clean water (such as rain puddles, water tanks, and irrigation ditches). Aedes mosquitoes (sometimes called "floodwater mosquitoes") lay eggs in moist environments with potential to be submerged; the eggs can withstand desiccation until a flooding event occurs.

(B) Eggs hatch into larvae that live in the water and come to the surface to breathe. Anopheles larvae lie in a horizontal position parallel to the water surface and do not have a siphon. Culex larvae maintain a position vertical to the water surface and breathe via a siphon, which extends to the water surface. Larva shed their skin (molt) four times during this stage before becoming pupae.

(C) Pupae float on the water surface. In the pupa stage, the head and thorax are fused to form a comma-shaped cephalothorax; during this stage, there are no distinguishing characteristics between the genera. Pupae breathe but do not feed, so larvicide cannot be ingested during this stage, although surface oil can induce suffocation. Metamorphosis from pupa into an adult mosquito takes about two days.