Quoc: The mosquito Anopheles gambiae is currently undergoing speciation into the M (opti) and S (avanah) molecular forms. Consequently, some pesticides that work on the M form no longer work on the S form. Over 3,500 species of the Culicidae have already been described. They are generally divided into two subfamilies which in turn comprise some 43 genera. These figures are subject to continual change, as more species are discovered, and as DNA studies compel rearrangement of the taxonomy of the family. The two main subfamilies are the Anophelinae and Culicinae, with their genera as shown in the subsection below. The distinction is of great practical importance because the two subfamilies tend to differ in their significance as vectors of different classes of diseases. Roughly speaking, arboviral diseases such as yellow fever and dengue fever tend to be transmitted by Culicine species, not necessarily in the genus Culex. Some transmit various species of avian malaria, but it is not clear that they ever transmit any form of human malaria. Some species do however transmit various forms of filariasis, much as many Simuliidae do.

How many different species of mosquitoes are there?
HW Chung: OK, some thoughts:
The relevant sentence in the passage is: Over 3,500 species of the Culicidae have already been described. The answer is Over 3,500.