The Southern House Mosquito (Culex quinquefasciatus) is a medium-sized mosquito found in tropical and subtropical regions of the world. It is the vector of lymphatic filariasis, avian malaria, and arboviruses including St. Louis encephalitis virus, Western equine encephalitis virus, zika virus and West Nile virus. It is taxonomically regarded as a member of the northern house mosquito (Culex pipiens) species complex. Its genome was sequenced in 2010, and was shown to have 18,883 protein-coding genes.
The adult southern house mosquito is a medium-sized mosquito and is brown in colour. The body is about 3.96 to 4.25 mm long. While the main body is brown, the proboscis, thorax, wings, and tarsi are darker than the rest of the body. The head is light brown, with the lightest portion in the center. The antennae and the proboscis are about the same length, but in some cases, the antennae are slightly shorter than the proboscis. The flagellum has 13 segments that may have few or no scales. The scales of the thorax are narrow and curved. The abdomen has pale, narrow, rounded bands on the basal side of each tergite. Males can be differentiated from females in having large palps and feathery antennae.
The larva has a short and stout head. The mouth brushes have long yellow filaments used for filtering organic materials. The abdomen consists of eight segments, the siphon, and the saddle. Each segment has a unique setae pattern. The siphon is on the dorsal side of the abdomen, and is four times longer than its breadth. The siphon has multiple setae tufts. The saddle is barrel-shaped and located on the ventral side of the abdomen, with four long anal papillae protruding from the posterior end.