Mosquitoes are taxonomically classified in the order Diptera along with other true flies. They have two pairs of functional wings but unlike other flies, their wings do not have scales. They also have another pair undeveloped pair of wing that is called halters. Mosquitoes are classified in the Family Culicidae, which contain 3 sub-families including Culicinae, Anophelinae and Toxorhynchitinae.
There are currently about than 3200 described species of mosquitoes worldwide (reference) and there are probably many more species waiting to be discovered. As of 2016, 176 species occurs in the United States (reference). Mosquito species are further classified into 38 genera with 34 belonging the subfamily Culicinae. Because of their diversity, Culicinae are classified into 10 different tribes. You can find the whole list of Culinae tribes and genera here. These Anophilinae contains 3 genera (Anopheles, Bironella, and Chagasia), whileToxorynchitinae contains the sole genus Toxorynchites.
Some of these mosquito species occur in the form of cryptic species which can be easily confounded. These cryptic species of mosquitoes form a complex. For instance, the Anopheles gambiae complex contains 6 closely related species including Anopheles gambiae (sensu stricto), Anopheles arabiensis are often difficult to distinguish.
Not all these species of mosquito vector diseases. In fact only a subset of the mosquito are know to transmit diseases to human and animals. Mosquitoes were first incriminated as host of vertebrate parasites in 1878. The species of mosquitoes that have medical importance belong to the genus Aedes (ex. Aedes aegypti), Anopheles ( ex. Anopheles gambiae) and Culex (ex. Culex pipiens). Some less medically important species also exist. They do cause diseases but not to the extent of the aforementioned mosquitoes.
Mosquitoes are also found in developed or industrialized countries like the United States, Europe, Australia and many others. Although mosquito cause some diseases in those countries like west Nile disease, zika, the main and common complaint is the discomfort caused by their bites.
Mosquito bites may cause irritation f the skin in humans and may cause blood loss to livestock. This could result in the reduction of the production and or death of the animals. See all other problems associated with mosquitoes beside disease transmission.